Particle Size Range Research Articles

Universal Dielectric Response in Electronically Correlated Functional Oxides CaCu3Ti4O12, LaFeO3, YFe0.5Cr0.5O3 and their Nanocomposites: A Comparative Study

AbstractCaCu3Ti4O12 (CCTO), LaFeO3 (LFO) and YFe0.5Cr0.5O3 (YFCO) were synthesized via conventional sol–gel auto–combustion method using citric acid as gelling agent. The X‐ray diffraction analysis revealed the phase purity of the samples. The energy dispersive X‐ray (EDX) analysis confirms the stoichiometry of the pristine phases. The average particle size obtained from the field emission Scanning electron microscopy (FE−SEM) images revealed that CaCu3Ti4O12 exhibits a broad range of particle size starting from a couple of hundreds of nanometer to micrometer, whereas that for LaFeO3 and YFe0.5Cr0.5O3 are about 110 nm and 50 nm, respectively. We have fabricated the new composites: CCTO–LFO, CCTO–YFCO and LFO–YFCO. The grain sizes of the composite phases are consistent with the pristine phases as they are prepared by at lower sintering temperatures and duration. The dielectric properties of these ceramic composites were compared to those of the pristine phases. The temperature and frequency dependent dielectric measurements reveal a wide range of dielectric constant with moderate tan δ values. The temperature dependent dielectric constant of the investigated samples varies from 100 to 1500 at room temperature and the data have been analyzed using universal dielectric response (UDR) model.

Production and recovery system for furan compounds from rice straw using an ionic liquid (1-methylimidazolium hydrogen sulfate) and vacuum steam distillation

Furan compounds, including 5-hydroxymethylfurfural and furfural, can be synthesized from biomass and have garnered attention for their potential applications in biofuels and resin precursors. In this study, the synthesis of the furan compounds from rice straw was explored using a combined approach of ionic liquid treatment, specifically 1-methylimidazolium hydrogen sulfate ([MIM]HSO4), and vacuum steam distillation. Through the optimization of various processing parameters, we established that the best conditions for the furan compound production include: a cold trap cooling temperature of – 196 ℃, a system pressure of 10 hPa, a treatment temperature of 180 ℃, a reaction duration of 30 min, a sample loading of 1wt%, and a particle size range of 45–90 µm. Under these conditions, the resultant yield of the furan compounds was quantified at 27.9wt%. Additionally, the recyclability of the utilized ionic liquid was evaluated. Notably, even after four recycling cycles (encompassing a total of five reactions), the yield of the furan compounds remained consistent, underscoring the viability of ionic liquid reuse.

Green synthesis of ZnO nanoparticles and its application for methyl green dye adsorption

This research presents a facile and inexpensive method for synthesizing ZnO nanoparticles using Nauclea latifolia fruit extract as a bioreductant and stabilizer. The prepared particles were characterized using some analytical techniques, including X-ray diffraction (XRD) for crystallinity and phase identification, scanning electron microscopy (SEM) to study surface morphology, Fourier transform infrared (FTIR) spectroscopy for functional groups analysis, transmission electron microscopy (TEM) for grain size analysis, UV–Vis spectroscopy for optical properties, and Brunauer-Emmett-Teller (BET) for surface area analysis. XRD analysis revealed a hexagonal wurtzite structure with an average crystallite size of 14.40 nm. FTIR showed absorption peaks at 3659, 1341, and 460 cm−1, corresponding to hydroxyl, carboxylic, and Zn–O, respectively. SEM image showed an agglomerated surface morphology with a flower-like shape. TEM estimated the particle size range to be 12.54–17.35 nm. UV–Vis scanning showed a broad peak at 373 nm. BET revealed 277.420 m2/g as the specific surface area. A batch adsorption experiment conducted on the performance of the nanoparticles for methyl green (MG) removal from aqueous solution showed highest efficiency of 99.96% at 60 min agitation time and pH of 7, with 0.05 g of the ZnO NPs, confirming the efficiency of the particles. The results of adsorption modelling revealed that the adsorption data were best fit to Freundlich isotherm and general-order kinetic models. Thermodynamic investigation confirmed the adsorption process as spontaneous, feasible, endothermic, and physical. Finally, the simplicity of the synthesis method and the performance evaluation of the ZnO nanoparticles indicate that an efficient and cost-effective adsorbent for MG recovery from aqueous solution has been successfully prepared.

The impact of incorporating waste materials on the mechanical and physical characteristics of tile adhesive materials

Abstract The goal of the investigation is to produce a cement mortar for building units and a high-performance ceramic tile adhesive by using V autoclaved aerated concrete as a partial substitute for cement. The combination consists of sand, crushed limestone, and polymeric additives. The experimental procedures were conducted utilizing contemporary laboratory equipment to facilitate the manufacturing of the product and the subsequent investigation of its characteristics, in accordance with the standards outlined in EN12004 and ASTM C1660. The laboratory tests carried out, which included splitting tensile strength, bonding strength, and open application duration, have demonstrated conformity to the product standards. The raw materials undergo many examinations prior to their utilization in the preparation process. The conducted tests encompassed chemical analysis, X-ray diffraction, and viscosity evaluation. These experiments aimed to ascertain the mixing ratios and determine the optimal quantity of water required for the preparation procedure. A thickness of 3 mm was employed, rendering it very cost-effective and environmentally sustainable due to the utilization of recycled resources. This particular adhesive possesses supplementary characteristics, such as its self-sufficiency on the site, since it is readily used without the need for extra materials, requiring only the addition of the necessary amount of water. Extensive research has been conducted on a range of mix designs and particle sizes for raw materials, together with varying proportions of additives, to determine the optimal ratio that satisfies both criteria and cost considerations. The adhesion strength of the building units was determined to be 7 N/mm2, surpassing the specified value in ASTM C1660. This indicates that the material is deemed successful and meets the required specifications for its application as a mortar for building units, as per the standard stating that an adhesion strength test exceeding 5 N/mm2 is necessary. The evaluation of the characteristics of the material employed as tile adhesive mortar was conducted in accordance with the EN1348 standard, revealing satisfactory compliance with all specified criteria. The application duration of the tile adhesive exceeds 25 min, while its tensile strength surpasses 10 N/mm2, thereby meeting the criteria for classification as a Class A tile adhesive.

Investigation of the homogeneity of particle suspension

The homogeneity of particle suspension has attracted more attention in the fields of rehydrating milk beverages. This work focus on size characterization of the floating, sticking (on the wall), suspended and settling particles involving both online and offline sizing techniques. Focused Beam Reflectance Measurement (FBRM) is a powerful online technique that is capable for measuring and analysing chord length distribution (CLD) of the suspended particles in liquid. It has been widely used in terms of monitoring size evolution of crystallization and sedimentation processes. In this work, a new approach that involves FBRM probe to measure the particle size distribution has been developed. The probe is placed at three different height levels in a standard container after one hour of free sedimentation. The results suggest that the finest fraction is dominant at all three heights but the percentage of it decreases with an increase of larger particles when looking at the bottom. Besides, all the floating, sticking and settling particles are collected and analysed, and the particle size distributions (PSDs) are obtained and compared using the offline sizing techniques, such as optical microscope and Camsizer. In the results, the suspended particle is the smallest one followed by the sticking and the floating particles, while the settling particle is the largest. However, for the sticking particles sticking on the wall, a great number of agglomerates is found during the test due to adhesion force, indicating that the size distribution might be overestimated. Based on the results, the target particle size range that can be stably suspended in the model suspension was selected by eliminating the unfavourable fractions.

Antimicrobial and Cytotoxic Effect of Positively Charged Nanosilver-Coated Silk Sutures.

Sutures are a crucial component of surgical procedures, serving to close and stabilize wound margins to promote healing. However, microbial contamination of sutures can increase the risk of surgical site infections (SSI) due to colonization by pathogens. This study aimed to tackle SSI by synthesizing positively charged silver nanoparticles (P-AgNPs) and using them to produce antimicrobial sutures. The P-AgNPs were reduced and stabilized using polyethylenimine (PEI), a cationic branched polymer. The physiochemical characteristics of P-AgNPs were confirmed from the surface plasmon resonance (SPR) peak at 419 nm, spherical morphology with a particle size range of 8-10 nm, PEI functional groups on NPs, a hydrodynamic diameter of 12.3 ± 2.4 nm, and a zeta potential of 31.3 ± 6 mV. Subsequently, the surfaces of silk sutures were impregnated with P-AgNPs at different time intervals (24, 48, and 96 h) using an ex situ method. Scanning electron microscopy (SEM) and tensile strength studies were conducted to determine the coating and durability of the NP-coated sutures. The NPs were quantified on sutures using inductively coupled plasma optical emission spectrophotometry (ICP-OES), which was in the range of 1-5 μg. Primarily, antimicrobial activity was studied using three microorganisms (Candida albicans, Streptococcus mutans, and Staphylococcus aureus) for both P-AgNPs and suture-coated P-AgNPs using the agar diffusion method. The results showed that only the NPs and NP-coated sutures exhibited enhanced antimicrobial effects against bacteria and fungi. Finally, the cytotoxicity of the sutures was investigated using stem cells from the apical papilla (SCAPs) for 24 h, which exhibited more than 75% cell viability. Overall, the results indicate that NP-coated sutures can potentially be used as antimicrobial sutures to diminish or inhibit SSI in postoperative or general surgery patients.

Impact of densification process on unprocessed biomass and post-hydrothermal carbonization

The pulp and paper industry use biomass residues, such as paper sludge and bark as fuel to provide energy for their plants. However, issues such as high-water content or low heating value limit the amount of energy that can be utilized. Processes to improve heat generation include biomass densification, which facilitates transportation and handling and can increase energy yield. However, the technical feasibility of briquetting is a function of the feedstock and preprocessing. This study introduces a novel approach to briquette production from biomass residues by utilizing wet biomass with water as a natural binder, contrasting with conventional methods that require forced drying and/or the addition of binders. The objective of this research was to investigate the impact of briquetting both unprocessed biomass and post-hydrothermal carbonization. The study focused on manufacturing briquettes derived from different sources, including bark (Balsam fir), paper sludge, and hydrochar of paper sludge. The feedstock was characterized for ash content and higher heating value. Biomass particle size (range), moisture content (range), process temperature (range), process pressure (range), and process residence time (range) were varied in briquetting experiments to determine conditions to produce high-quality briquettes with minimal energy input. Moisture content as high a 50 wt% in feedstock produced technically feasible briquettes, with appropriate physical-mechanical properties (durability, volumetric expansion and apparent density), and energetic potential (calorific value). The addition of heat (pressing temperature of 150 °C) during the pressing process resulted in briquettes with enhanced physical-mechanical, and energetic properties, surpassing those produced at room temperature. Further tests with additional steps in the production process are required to meet commercialization standards in Canada, but the treatments conducted in this study effectively improved the energy potential of biomass for internal industrial energy gains.

Industrial application and numerical simulation on discrete dynamics of fine particulate matters: Condensational growth, deposition and agglomeration

The removal effects of multiple discrete dynamic mechanisms on particulate matters (PMs) are of great significance for industrial application and basic research. In this work, a wet phase transition agglomerator (WPTA) is installed between a wet electrostatic precipitator (WESP) and a stack at a 280 t/h coal-fired power plant. The removal effects of the WPTA are compared with those of the WESP by field measurement. Meanwhile, a numerical model for predicting particle size distributions is developed and verified through the experimental data. The results indicate that the WPTA reduces the emission concentrations of PM1 and PM2.5 to 0.64 mg/Nm3 and 0.89 mg/Nm3, respectively. The PM1 removal efficiencies for the independent WPTA, the independent WESP and the combined method are 33.07 %, 40.31 % and 58.36 %, respectively. The microscopic morphologies of the fine PMs in the particle size range of 0.98–1.64 μm exhibit blocky, spherical and crystal structure. The simulated errors of PM1, PM2.5 and PM10 are 7.81 %, 7.87 % and 12.27 %, respectively. The boundary layers of the tube bundle are conducive to strengthening thermophoretic force and supersaturation. Consequently, the WPTA can effectively replace the WESP to achieve the emission control of fine PMs in industrial applications. The developed numerical model can accurately predict the particle size distributions in the WPTA.

Storability and Brewing Quality of Corn Grits: Impacts of Storage Temperature, Particle Size and Key Compositional Factors

Across international brewing operations corn grits from different suppliers vary substantially in terms of their physical properties and chemical composition. Present research aimed to highlight the key factors determining the brewing quality of stored corn grits. Six grits samples were sourced with different particle sizes (that ranged from 0% to 74% of particles ≤0.355 mm) and stored at 10 °C, 20 °C, or 30 °C for 0, 2, 4, 8, 12, and 16 months. Samples were analysed for moisture, extract, lipid, trihydroxy fatty acids (THFA) and pro-oxidant metal ion contents. Particle size range was measured using sieve analysis. Increasing levels of THFA occurred on storage due to lipid oxidation and are negative indicators of brewing quality. PLS-R modelling of THFA levels (R 2 = 0.83) revealed particle size (hence surface area for oxidation) was the most important factor (∼60% of the total R 2) followed by storage time (∼25%) and temperature (∼7%). Metal ion content and lipid content of grits were minor contributors. Results showed that coarser milling of grits offers protection against lipid oxidation even after 8 months at 30 °C. These insights into key factors determining the rate of lipid oxidation in stored corn grits will help to develop better supply chain management and storage practices with which to assure their brewing quality.

Evaluation of the spatial distribution of aerosols produced by various respiratory activities

This study investigated the dispersion and evaporation characteristics of droplets and droplet nuclei emitted during human respiratory activities. A specially designed wind tunnel was filled with purified air, wherein selected subjects performed various respiratory activities with their heads positioned inside. An optical particle sizer was used to collect particles with sizes of 0.3–10 μm at 63 points in front of the mouth. The dilution factors were analyzed to investigate the impact of combining the exhaled airflow with ambient air on droplet evaporation. At a distance of 0.01 m from the mouth opening, the volume concentration of the particles was the highest during breathing, followed by coughing and speaking. The volumetric concentration of particles decreased with an increase in the distance from the inlet for all activities. The spatial volume concentration distribution of particles showed that coughing tended to disperse the particles in the forward direction, whereas speaking tended to disperse them laterally. Utilizing these findings in CFD analysis can provide in-depth insights into dispersion and evaporation dynamics. This can contribute significantly to the development of preventive measures through the implementation of proactive HVAC systems to effectively remove infectious particles and control the spread of infectious diseases. Future studies should explore a wider range of particle sizes and advanced sampling techniques for a clear understanding of respiratory particle dynamics and infection control strategies.

Material removal rate model for chemical–mechanical polishing of single-crystal SiC substrates using agglomerated diamond abrasive

Material removal mechanisms are essential for the selection of polishing slurries and parameter optimization of chemical–mechanical polishing (CMP) processes. This study established a material removal rate (MRR) model for CMP of single-crystal SiC substrates using a fixed agglomerated diamond (AD) abrasive pad (FADAP). The distribution of the polishing pressure between the AD abrasive and FADAP matrix was examined, and the influence of the abrasive and polishing parameters on the MRR was revealed. Furthermore, single-factor experiments were conducted to validate the rationality of the MRR model. The experiments demonstrated that when the thickness of the surface-affected layer of the single-crystal SiC substrate in the MRR model was set to 5 nm, the error between the calculated and experimental values of the model could be controlled to within 20%. This result experimentally verified the validity of the MRR model and its associated assumptions. Moreover, the MRR of the CMP process of a single-crystal SiC substrate reached 36.26 μm/h with a polishing pressure of 27.6 kPa and an AD abrasive primary particle size range of 7–10 μm. Therefore, the feasibility of efficiently processing single-crystal SiC substrates using an FADAP was theoretically confirmed.

In Situ Ca‐ and Mg‐ Codoped Biochar Derived from Tobacco Stem for Phosphate Adsorption and Desorption

AbstractPhosphorus is an important element for plant growth. The efficient use and recovery of phosphorus is crucial due to limited phosphate resource reserves. This study explored the potential application of an in situ Ca and Mg co‐doped biochar derived from tobacco stem to reclaim and reuse phosphate from aqueous solutions. We performed various batch adsorption experiments and industrial analysis based on different parameters. The findings indicate that biochar prepared using the raw material particle size range of 0.85–2 mm and pyrolyzed at 800 °C presented good pore structure and specific surface area. Ca and Mg elements in biochar exhibited great influence on its phosphate adsorption property. The maximum phosphate adsorption capacity of the tobacco stem‐based biochar was 54.66 mg/g, and the experimental data agreed with the Langmuir equation, suggesting monolayer adsorption. The adsorption process conformed to the pseudo‐second‐order kinetic equation, indicating that chemisorption was the dominant adsorption process and that the adsorption was controlled by intra‐particle diffusion. Furthermore, phosphate adsorbed on tobacco stem‐based in situ Ca and Mg co‐doped biochar was released under acidic, alkaline, and neutral conditions. Therefore, in situ Ca and Mg co‐doped biochar prepared from tobacco stems is a potential environmentally friendly and low‐cost adsorbent for phosphorus recovery.

Polyurethane modified asphalt mixture incorporating waste glass with a wide particle size range: Preparation and performance evaluation

Increasing the utilisation rate of waste glass in asphalt mixtures, especially that with a wide range of particle sizes, is of great importance to resource recycling, while it may bring drawbacks to the engineering performance of asphalt mixtures. Incorporating polyurethane (PU) as a modifier can enhance asphalt mixture's performance, but there is limited research considering the usage of waste glass as aggregates. In this study, PU modified asphalt mixtures were prepared, incorporating waste glass particles ranging in size from 2.36 mm to 9.5 mm as a portion of the aggregates. Optimal preparation methods and mix designs for the PU-modified asphalt binder were determined through a series of tests designed based on Orthogonal method. The performances of the PU-modified asphalt binders were then evaluated to guide the selection of the optimal preparation method and mix design. PU-modified waste glass asphalt mixtures were then prepared and their engineering performances were assessed at various glass-to-aggregate ratios. The results show that scheme PU-1 with a shearing temperature of 140°C, a shearing time of 10 min, a PU content of 10% and a compatibiliser content of 2% is suggested for preparing the PU-modified asphalt binder, which shows the best performances due to superior chemical modification and compatibility. Higher glass content decreases the high/low-temperature performance, but it can be improved by adding silane coupling agent or hydrated lime, with the latter showing better results. The incorporation of glass particles has little impact on anti-sliding performance, and asphalt mixtures maintain excellent anti-sliding properties up to a 20% replacement rate. Overall, the performance of the asphalt with waste glass up to 15% can meet the specification requirements. This novel approach offers a potential solution to enhance the incorporation of waste materials in asphalt construction, contributing to sustainable and environmentally-friendly road construction.

Evaluating the Role of Titanomagnetite in Bubble Nucleation: Rock Magnetic Detection and Characterization of Nanolites and Ultra‐Nanolites in Rhyolite Pumice and Obsidian From Glass Mountain, California

AbstractWe document the presence, composition, and number density (TND) of titanomagnetite nanolites and ultra‐nanolites in aphyric rhyolitic pumice, obsidian, and vesicular obsidian from the 1060 CE Glass Mountain volcanic eruption of Medicine Lake Volcano, California, using magnetic methods. Curie temperatures indicate compositions of Fe2.40Ti0.60O4 to Fe3O4. Rock‐magnetic parameters sensitive to domain state, which is dependent on grain volume, indicate a range of particle sizes spanning superparamagnetic (<50–80 nm) to multidomain (>10 μm) particles. Cylindrical cores drilled from the centers of individual pumice clasts display anisotropy of magnetic susceptibility with prolate fabrics, with the highest degree of anisotropy coinciding with the highest vesicularity. Fabrics within a pumice clast require particle alignment within a fluid, and are interpreted to result from the upward transport of magma driven by vesiculation, ensuing bubble growth, and shearing in the conduit. Titanomagnetite number density (TND) is calculated from titanomagnetite volume fraction, which is determined from ferromagnetic susceptibility. TND estimates for monospecific assemblages of 1,000 nm–10 nm cubes predict 1012 to 1020 m−3 of solid material, respectively. TND estimates derived using a power law distribution of grain sizes predict 1018 to 1019 m−3. These ranges agree well with TND determinations of 1018 to 1020 m−3 made by McCartney et al. (2024), and are several orders of magnitude larger than the number density of bubbles in these materials. These observations are consistent with the hypothesis that titanomagnetite crystals already existed in extremely high number‐abundance at the time of magma ascent and bubble nucleation.

Characterization and therapeutic potential of chitosan‐zinc oxide nanostructured particles synthesized using crab shell derived biopolymer

AbstractThe development of novel drug candidates for treating microbial infections and cancer turns into a challenging task. The biopolymer‐based nanomaterials have gained popularity for their effective roles in the pharmaceutical sector. The present investigation aims to valorize crab shell wastes to extract chitosan. The obtained (chitosan) biomass was utilized to synthesize chitosan‐zinc oxide nanoparticles (Ch‐ZnO‐NPs). The nanomaterial characterization was achieved by a variety of physicochemical techniques including UV, Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), elemental analysis, and High‐resolution transmission electron microscopic (HR‐TEM) examination. The synthesized nanomaterials have a particle size range of 35–80 nm and are more stable with a zeta potential value of (−40.78) mv. Additionally, the designed nanomaterials were utilized to evaluate the biological efficiency. The minimal inhibitory concentration value of Ch‐ZnO‐NPs was observed as 10 μg/mL. The designed nanomaterials significantly reduced the growth of Vibrio alginolyticus and Bacillus cereus and inhibited biofilm formation. The synthesized Ch‐ZnO‐NPs unveiled cytotoxic effects on A549 cells with an IC50 (half‐maximal inhibitory concentration) of 20 μg/mL. Furthermore, substantial increase in cell death was noticed in A549 cells treated with Ch‐ZnO‐NPs. Consequently, this investigation concludes that Ch‐ZnO‐NPs may act as a biomedicine.

Comparative Evaluation of Analytical Techniques for Quantifying and Characterizing Polyethylene Microplastics in Farmland Soil Samples

The presence of microplastics in soil has become a significant global concern, posing a threat to environmental, agricultural, and human health. However, the use of various detection methods has led to significant discrepancies in the statistics reported for the abundance of soil microplastics across the available literature, resulting in poor comparability across the available literature. Studies have shown that plastic film residue is among the main primary sources of microplastics in farmland soils. Therefore, we manufactured and selected polyethylene microplastics (PE-MPs) from plastic film and combined them with soil samples after density separation treatment, forming a spiked test soil sample, which was subjected to density separation and extraction using a ZnCl2 solution. The experiment used visual inspection by stereo microscopy, micro-Fourier transform infrared spectroscopy, micro-Raman spectrometry, laser direct infrared imaging, and pyrolysis-gas chromatography–mass spectroscopy for the quantitative analysis of spiked soil. This study systematically assessed and compared these five common soil microplastic detection methods. The results revealed different quantitative detection accuracies across various particle size ranges. Micro-Fourier transform infrared spectroscopy showed a broader applicable particle size range (20–5000 μm) and higher detection rate (91%), while the detection range (>50 μm) and rate (70%) of visual inspection through stereo microscopy were lower. For the identification of microplastic morphology, laser direct infrared imaging performed better, whereas micro-Fourier transform infrared spectroscopy had the advantage in determining the types of polymers present over micro-Raman spectrometry. The advantages, disadvantages, and detection rates of the above five detection methods were clarified during the detection process. Considering these findings and similar studies, we suggest three combinations of the evaluated methods to optimize the detection of PE-MPs.

Formulation and Antimicrobial studies of Microencapsulated Musanga cecropioides Stem Bark Extract

Microencapsulation is the process of coating small droplets of liquid or solid materials with a continuous film of polymeric substances. The aim of the research was to formulate microparticles of Musanga cecropioides stem bark extract. The dried, powdered stem bark of Musanga cecropioides was extracted by maceration. The aqueous extract was microencapsulated using polymers such as alginate, pectin and hydroxylpropyl methylcellulose acetate succinate (HPMCAS) by counter-ion coacervation method using an electrostatic droplet generator. The formulated microcapsules were evaluated for flow properties, particle size, drug content, antimicrobial activity and in vitro release kinetics in simulated gastric and intestinal fluids. The microparticles were subjected to stability tests under different temperature (45°C, 25°C and 8°C) and relative humidity (100% RH, 78% RH and 0% RH) conditions for a period of three (3) months. The mean particle size of the microcapsules decreased with increasing applied voltage of the electrostatic generator. Particle size range for the batches of formulated microparticles was 68.20-223.84µm. The percentage entrapment efficiency of the batches of microparticles ranged from 80.26-86.58%. The microparticles lost a significant percent of its drug content after storage at different temperature and relative humidity conditions. The formulated microparticles and crude extract possess significant antibacterial action against both gram positive and negative bacteria as well as antifungal effect against C. albicans. Microparticles of M. cecropioides extract were formulated by counter-ion coacervation method using an electrostatic droplet generator which conferred advantages of sustained drug release, reduced frequency of dosing, masked unpalatable taste, improved stability and enhanced patient acceptance on the crude extract.

Исследование гранулометрического состава измельченного продукта, полученого при измельчении доломита в центробежной мельнице вертикального типа

Introduction. Modern medium (10–200 microns) and fine (0.1–10.0 microns) powders have a high cost, which limits the scale of their production and use. This assumes the implementation the latest achievements in the field of creating new equipment that is not inferior in its technical characteristics to the best foreign models into industry. The use centrifugal mills of vertical type for grinding various raw materials has shown their high efficiency in obtaining materials in the range – 0.2–0.01 mm. Studies of these mills operation under various operating conditions made it possible to create a large data set on the dependence of the crushed material granulo-metric composition on the design features of the mills and technological parameters of the grinding process. The results of a previously study of the granulo-metric composition a finely dispersed crushed product integral distribution according to particle size classes less than 80 microns were presented. They were obtained in a Brookhaven BI-XDC X-ray analytical centrifuge by measuring particle sizes in natural sedimentation mode, when the centrifuge disk was stationary during the experiment. The studies of the particle size differential distribution of a finely dispersed crushed product according to particle size classes less than 80 microns, which have not been carried out to date are of particular interest. Purpose of the study. The differential distribution study of the finely dispersed granulo-metric product composition obtained by grinding lump dolomite in a centrifugal mills of vertical type under different operating modes. Materials and methods. To solve this problem, samples of crushed material were taken from grinding dolomite from the Bosninsky deposit (RNO-Alania) in a centrifugal mill of the vertical type MV-0.3 with a 300 mm rotor diameter with following technological modes of the grinding process: mill rotor speed n = 310; 360 min–1, height of the material column above the rotating rotor H = 180; 270 mm, test time – 6 hours. Selected samples with a size class of –0.08 mm were analyzed in an X-ray analytical centrifuge Brookhaven BI-XDC, designed to determine the particle size distribution in the range from 0.01 to 100 microns. The measurements were performed on a suspension prepared from a mixture of 0.5 g of the selected sample with a 20% solution of sucrose and distilled water. Samples with a size class of 0.08 mm were weighed on laboratory scales LV SP.005.048 RE. The resulting suspension was dispersed in an ultrasonic bath for 3–5 minutes. After dispersion, the suspension was poured into the analyzer disk. While stirring, the lower absorption baseline line of a homogeneous particle suspension was measured. The obtained data from the analysis of the fine fractions size of were processed by the centrifuge computer software and graphs of the differential distribution of particles were constructed for various technological modes of grinding dolomite in a centrifugal mill. During the processing of the experiments, minor bursts in the concentration of the crushed product were not taken into account. The results and discussion. For the first time, a differential analysis of the granulo-metric composition of finely dispersed material with a particle size of –0.08 mm, obtained by grinding lump dolomite in a centrifugal mill of the vertical type under different mill operating modes, was carried out. Under all investigated operating modes of the centrifugal mill, the main part of the fine fraction in the mill outlet was in the range from 1.197 to 4.643 μm, and in steady-state operation it varied from 1.310 to 4.601 μm. The range of fine particle sizes has maximum values when the height of the column of crushed material above the rotating mill rotor and the rotation speed of the mill rotor decrease, and minimum values are observed when the height of the column of crushed material above the rotating mill rotor increases and the rotation speed of the mill rotor increases. Resume. 1. The article presents the results of the granulo-metric composition differential distribution study of a finely dispersed product obtained by grinding lump dolomite in a centrifugal mill of the vertical type. 2. The conducted studies have shown that, despite the positive results in obtaining fine particles with a size of 0.001 microns (nanoparticles) by mechanical means, the industrial production of nano-materials when grinding lump mineral raw materials in a vertical centrifugal mill is not economically profitable due to the low specific productivity and high energy intensity of the grinding process. 3. The obtained research results can be useful in the design of centrifugal mills.

Fabrication of Amisulpride Nanosuspension for Nose to Brain Delivery in the Potential Antipsychotic Treatment

ABSTRACT: Background: This research was aimed with the development of antipsychotic drug delivery for olfactory administration which could deliver drug to the brain. Amisulpride is a psychoactive drug that belongs to the benzamide derivatives class. It enhances dopaminergic neurotransmission by inhibiting presynaptic dopamine D2/D3 auto receptors selectively at lower dosages. Method: The nanosuspension was prepared by media milling technique for nose to brain delivery. The nose to brain delivery developed an effective route to bypass the BBB and deliver the drug to the brain. Factorial design was used for the designing and optimizing formulation based on various process and formulation factors. The optimized batch further analyzed to determine particle size, PDI, zeta potential, and drug content. With appropriate selection of process parameters like speed and bead amount. The media milling method is one of the effective methodology to reduce particle size and with the help of stabilizers nanoparticles could be stabilised. Result: The average particle size range of nanosuspension batch was observed 100-150 nm with a polydispersity index of 0.0927, Zeta potential +39.14 mV and drug content 88.12 ± 2 %. Conclusion: Intranasal administration is a promising alternative for bypassing the blood-brain barrier, reducing the adverse effects, and lowering the doses.

Production and Characterization of Ni0.50 Al0.50 and Ni0.55 Al0.45 Powders by Volume Combustion Synthesis

Nickel aluminide (NiAl) is an essential intermetallic material with a high melting point and excellent high temperature corrosion resistance. It is a solid solution of Ni and Al in 40-61 mol.% Ni range. In this study, Ni0.50Al0.50 and Ni0.55Al0.45 powders were formed by using nickel and aluminum elemental powders through volume combustion synthesis (VCS). MgO powder was utilized as the thermal diluent. According to adiabatic temperature calculations, MgO was added to the reactant mixture in 10-40 vol.% range for preventing the melting and sintering of the formed Ni0.50Al0.50 and Ni0.55Al0.45 particles. After VCS, the products were ground into powder form and leached in 3M HCl solution in order to remove the MgO particles. After VCS, the samples which were obtained with 10 - 30 vol.% MgO addition were quite hard and difficult to grind. This indicated the partial sintering of the formed particles. It was relatively easier to grind into powder form the samples which contained 40 vol.% MgO. Therefore, it was determined that the most suitable MgO ratio for the formation of Ni0.50Al0.50 and Ni0.55Al0.45 powders was 40 vol.%. Formed powders were mostly in 5-100 µm particle size range. The formation of single phase pure powders was confirmed by the XRD analyses. A shift of about 0.1 degrees to higher 2-theta values was determined in the XRD peaks of the Ni0.55Al0.45 powder as compared to the Ni0.50Al0.50 phase, after annealing the powders. The results were in agreement with the crystallographic data.