Laser Diffraction Particle Size Research Articles

Experimental Study on Mechanical Properties of Recycled Aggregate Mixed Soil

In the context of efforts aimed at reducing carbon emissions, the utilization of recycled aggregate soil mixes for soil stabilization has garnered considerable interest. This study examines the mechanical properties of mixed soil samples, varying by dosage of a soft soil curing agent C, recycled aggregate R content, and curing duration. Mechanical evaluations were conducted using unconfined compressive strength tests (UCS), field emission scanning electron microscopy (FESEM), and laser diffraction particle size meter tests (PSD). The results indicate that the strength of the mixed soil samples first increases and then decreases with higher dosages of recycled aggregate, reaching optimal strength at a 20% dosage. Similarly, an increase in curing agent dosage enhances the strength, peaking at 20%. The maximum strength of the mixed soils is achieved at 28 days under various proportions. The introduction of the curing agent leads to the formation of a flocculent structure, as observed in FESEM, which contributes to the enhanced strength of the soil mixes. Specimens prepared with a combination of 20% R and 20% C, maintained at a constant moisture content of 20%, and cured for 28 days exhibit a balance between economic, environmental, and engineering performance.

Alumina-supported multi-metal catalyst for e-waste management for reclamation of valuable products

ABSTRACT Electronic and electrical waste (e-waste) has increased exponentially due to the humungous growth in the information technology and communication sector. Many multi-metal catalysts are developed by researchers for electronic waste plastic conversion into fuel products and recovery of valuable metals. In the present study, an Alumina-supported catalyst powder with selected transition metals metal oxides was prepared to improve the yield of hydrocarbon liquids. FESEM with energy-dispersive spectroscopy, XRD and laser diffraction particle size analysis were used to characterise catalysts. The shredded e-waste chips to catalyst weight ratio was maintained from 2:1 to 10:1 and studied. The experiments were conducted with a reaction temperature range from 300°C to 500°C. The produced fuel density was 0.88 kg/L, with 0.75 liquid fuel conversion and 71.7% overall liquid fuel yield. The light gas percentage was 4–6%. NMR analysis, bomb calorimetric study and gas chromatography-mass spectroscopy of liquid fuel analysis suggest carbon chain compounds of C3–C20 hydrocarbon, indicating a mixture of petrol and diesel-like liquid products. The catalyst can be tuned to improve liquid fuel conversion. The liquid fuel product is promising for fuel use, however, upgrading treatments are needed to meet standard product specifications.

Reconciling Coulter Counter and laser diffraction particle size analysis for aquaculture monitoring

The disaggregated inorganic grain size (DIGS) of bottom sediment analyzed with a Coulter Counter (CC) has been used to show that the fraction of sediment deposited in flocs (floc fraction) increased in both the near and far field after the introduction of open cage salmon aquaculture, altering benthic habitat and species composition. As a result, DIGS was identified as a potential indicator of regional environmental changes due to aquaculture. Laser diffraction is an attractive alternative to the CC because of its greater efficiency and larger size range. To determine if a laser diffraction instrument, Beckman-Coulter LS 13 320 (LS), could replace the CC within a Canadian national aquaculture monitoring program, the DIGS of 581 samples from five different regions in eastern Canada were analyzed with an LS and a CC. Results show that the LS could not be used to calculate floc fraction. Instead, % sortable silt and the volume % of inorganic particles < 16 µm were evaluated as alternative proxies for fine sediment properties. LS and CC values for these parameters were correlated, but they were significantly different and the relationship between the instruments was dependent on the area sampled. The LS did not capture variations between areas seen in the CC DIGS data. Where the DIGS from the CC found no sorting in the finest size classes, all the LS samples had similar size distributions characterized by smooth modal peaks. The LS and CC both return values that can be used to monitor changes in the deposition of fine-grained sediment, but the LS cannot determine changes in floc deposition and caution is required if comparing different sedimentary environments.

Vibrations of viscoelastic FG porous graphene-platelets reinforced doubly-curved shells via experimental characterisation of graphene platelets

This work explores the vibrations of viscoelastic functionally-graded (FG) porous graphene-platelets reinforced doubly-curved shallow shells via experimental characterisations of graphene platelets. In particular, the effects of ultrasonication time of graphene platelets, on the vibrations of graphene-platelets reinforced shells, are studied. This is of interest because graphene platelets are often ultrasonicated in solvents to achieve better dispersions during the fabrication of graphene-platelets/epoxy composite structures. In this study, geometric characteristics of the graphene platelets under different sonication times are quantitatively and qualitatively analysed through experimental characterisation techniques, including a laser diffraction particle size analyser, a scanning electron microscopy (SEM), and a scanning force microscopy (SFM). The geometric characteristics of graphene platelets are considered in the effective material properties using a micromechanics model of Halpin-Tsai. Different FG distributions of graphene platelets and closed-cell porosity are modelled. The Kelvin-Voigt viscoelastic model is used to consider the internal friction-induced energy dissipation for the polymeric composite shell. Hamilton’s variational principle and an assumed mode method are used to derive and solve the equations of motion, respectively, for the vibrations of the doubly-curved shells. The effects of graphene platelets sonication time, in combination with the effects of graphene platelets weight fraction, porosity coefficient, FG distributions, shell thickness ratio, and shell curvature radii, are scrutinised. The results show that increasing ultrasonication time reduces the shell’s out-of-plane dimensionless fundamental frequency as a result of the reduction in graphene platelets aspect ratio.

Cyclic reduction of combusted iron powder: A study on the material properties and conversion reaction in the iron fuel cycle

Recently, iron powder has been proposed as a high energy density, easily storable, and CO2-free energy carrier. During the iron combustion, thermal energy is released as heat. The combusted products, the iron oxide particles, are captured and cyclically reduced back into iron powder in a process that is powered by renewable energy. Each combustion step, followed by a reduction, constitutes one cycle in the process. Previous studies predominantly focused on the reduction and combustion as individual steps. This work investigates the impact of cyclic combustion-reduction on material properties, with the specific focus on the reduction of iron oxides using hydrogen under fluidisation conditions. The powder is combusted and reduced for 3 cycles under the same conditions. Afterwards the properties of the powder and the reaction conversion are characterized. The physical techniques used for size and shape analysis include laser diffraction particle size analysis and scanning electron microscopy (SEM). For structure and chemistry, X-ray diffraction (XRD) and energy dispersive X-ray (EDX) analysis are also employed. To study the effect of the reduction conditions on the cycle and on the material properties of the powder, different experiments are conducted using 550 and 575°C as reduction temperatures. The higher conversion is observed at 575°C. During the first combustion particles resulted in large agglomerates and required a manual grinding step before being sent to the next reduction. However, the particle size distribution remains relatively stable in all subsequent cycles. The results suggest that the powder can be effectively utilized in the iron fuel cycle without requiring additional intermediate treatments, such as grinding and sieving after each cycle. This aspect highlights the potential feasibility and simplicity of implementing the cyclic combustion-reduction process for practical applications of iron powder as an energy carrier.

Degradation of tannic acid using monopersulfate activated CuO particles

A Copper(II) oxide material was synthesized and its efficiency in degrading Tannic acid (TA) was investigated using ultraviolet (UV) irradiation and CuO activated peroxymonosulfate (PMS). The CuO particle catalyst exhibited exceptional activity and was characterized using XRD, SEM, Raman spectroscopy, and laser diffraction particle size analysis (LDPS). The influence of calcination temperature, UV power, PMS dosage, CuO dosage, and coexisting anions on the degradation rate of TA was examined. The research results demonstrate that the addition of a structural guide enhances the catalytic performance of CuO. Among the different calcination temperatures investigated, CuO calcined at 500 °C demonstrates the best catalytic performance and achieves the highest degradation efficiency under neutral conditions. Under the optimal conditions of 0.1 g/L CuO and 1.2 mmol/L PMS, the TA degradation rate of 15 mg/L within 40 min was 97.69%, and the total organic carbon removal rate was 69.85%. Quenching experiments confirmed the participation of multiple active species in the decomposition process. After five experimental cycles, the CuO material maintained a TA removal rate above 92%. Furthermore, HPLC-MS analysis was employed to identify potential intermediates in the degradation of TA.

Influence of filtering on the effective concentration and sterility of a 2% cyclosporine ophthalmic solution: a quality improvement perspective

BackgroundPharmaceutical companies do not sell formulations for all diseases; thus, healthcare workers have to treat some diseases by concocting in-hospital preparations. An example is the high-concentration 2% cyclosporine A (CyA) ophthalmic solution. Utilizing a filter in sterility operations is a general practice for concocting in-hospital preparations, as is the case for preparing a 2% CyA ophthalmic solution. However, whether filtering is appropriate concerning the active ingredient content and bacterial contamination according to the post-preparing quality control of a 2% CyA ophthalmic solution is yet to be verified.MethodsWe conducted particle size, preparation concentration, and bacterial contamination studies to clarify aforementioned questions. First, we measured the particle size of CyA through a laser diffraction particle size distribution. Next, we measured the concentration after preparation with or without a 0.45-µm filter operation using an electrochemiluminescence immunoassay. Finally, bacterial contamination tests were conducted using an automated blood culture system to prepare a 2% CyA ophthalmic solution without a 0.45 μm filtering. Regarding the pore size of the filter in this study, it was set to 0.45 μm with reference to the book (the 6th edition) with recipes for the preparation of in-hospital preparations edited by the Japanese Society of Hospital Pharmacists.ResultsCyA had various particle sizes; approximately 30% of the total particles exceeded 0.45 μm. The mean ± standard deviation of filtered and non-filtered CyA concentrations in ophthalmic solutions were 346.51 ± 170.76 and 499.74 ± 76.95ng/mL, respectively (p = 0.011). Regarding bacterial contamination tests, aerobes and anaerobes microorganisms were not detected in 14 days of culture.ConclusionsDue to the results of this study, the concentration of CyA may be reduced by using a 0.45-µm filter during the preparation of CyA ophthalmic solutions, and furthermore that the use of a 0.45-µm filter may not contribute to sterility when preparing CyA ophthalmic solutions.

Characterization of spray dried cellulose nanofibrils produced by a disk refining process at different fineness levels

Three types of wood pulp feedstocks including bleached softwood kraft, unbleached softwood kraft and old corrugated containers were disk refined to produce cellulose nanofibrils at different fineness levels ranging from 50 to 100%, and the resulting aqueous suspensions of cellulose nanofibrils were spray dried. The spray drying experiments were carried out to examine different processing conditions for the different CNF feedstock types and fines level at various suspension concentrations to produce dry samples with free-flowing powder morphologies. The fineness levels and solids contents of CNF suspensions were set to 80% or more and 1.8% or less, respectively. If the solids content of the CNF solutions was high and the fibrillation level was low, plugging was experienced in the spray head because of the high viscosity of the suspensions, resulting in production of poor-quality powders. In terms of reduction in processing energy, even if the CNF suspension solids content was increased to 1.5 wt.%, the powder quality and the production yields were excellent. It was confirmed that high-quality powder under 20 µm were produced at a 90% fibrillation level of all CNF feedstocks. The resulting dry CNF powders were characterized to determine particle size distributions and morphological properties via a scanning electron microscope and a laser diffraction particle size analyzer. The particle sizes were smaller at higher fibrillation levels and lower solids content of the CNF suspensions. The CNF suspension derived from bleached kraft pulp, the average particle size decreased by 43% and 33% with the lowered solids contents from 1.8 to 1%, and the increased fineness levels from 80 to 100%, respectively.

Experimental study on the mechanical properties and cementation mechanism of microbial cemented fine tailings backfill

The extensive exploitation of metal mines has resulted in the generation of vast quantities of fine tailings, posing significant environmental challenges such as surface subsidence and deposition. The conventional cemented backfill technology, which has been widely used for tailings processing, requires substantial cement consumption and thus leads to escalated economic costs and carbon emissions. In this paper, we propose a pollution-free alternative, Microbial-Induced Calcite Precipitation (MICP) technology, as a promising solution for sustainable mine filling. The study employs microscopic and macroscopic analysis techniques, including laser diffraction particle size (LDPS) analysis, scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), to investigate the inner structure and mechanical properties of the microbial cemented fine tailing backfill (MCFB). Key parameters such as unconfined compressive strength (UCS), CaCO3 content and porosity are examined, with a focus on the effects of bacterial solution dosage and curing time. The results reveal that the MICP-processed fine tailings exhibit an increase in particle size by approximately 292.1% compared to their original size. Furthermore, MCFB specimens demonstrates significantly enhanced UCS and decreasing porosity under comparable conditions, surpassing the performance of traditional cemented fine tailings backfill (CFB) specimens. Microscopic analysis highlights that the strength development in MCFB predominantly arises from the cementation effects of MICP-induced CaCO3, primarily in the form of calcite, rather than the cementation effects resulting from hydration products (C-S-H) in conventional CFB.

Fabrication and characterization of coated ceramic membranes from natural sources for water treatment applications

This study aimed to fabricate ceramic membranes for water treatment applications using natural and cost-effective materials. This is the first-time white clay, Arabic gum, and marble powder were used in ceramic membranes. Two ceramic membranes were fabricated using an extrusion process: substrate A and substrate B. The JMP software (Version 15) was used to obtain the optimal recipes for the two substrates, which were white clay (62.7 %), silica flour (32.3 %), and Arabic gum (5 %) for substrate A and white clay (63 %), silica flour (26.8 %), and marble powder (10.2 %) for substrate B. Additionally, the effect of waste glass in the coating layer on the separation rate was examined. The ceramic membranes were analysed using various techniques, including X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), laser diffraction particle size analysis, thermogravimetric analysis (TGA), and a universal testing machine. The morphologies of the membranes were observed using scan electron microscopy (SEM), and their chemical resistances were evaluated. The flux across the substrates was measured using a crossflow filtration system, and it was found that substrate B had a higher flux (116 L/m2h) than substrate A (77 L/m2h). This was probably due to its higher porosity (34 %) compared to substrate A (29 %). Substrate A, with a coating layer (CO-2), exhibited the highest removal efficiency of approximately 99.2 % for synthetic feed water composed of tap water and bentonite clay, with an average particle size of 1.1 μm and turbidity of 13 ± 0.2 NTU. The costs of ceramic membranes A and B were estimated to be approximately 51 and 47 USD/m2, respectively. Their cost-effectiveness results from the use of low-cost materials that do not require high sintering temperatures. This study demonstrates that these ceramic membranes are not only affordable but also possess desirable properties for water treatment applications.

Selective recovery of vanadium from high-chromium vanadium slag by a mechanically activated low-sodium salt roasting-water leaching process

Stabilizing the toxic element chromium and improving vanadium recovery are crucial for the economic and efficient treatment of high chromium-bearing vanadium slag. This study employed mechanical activation to enhance vanadium extraction from high chromium-bearing vanadium slag through a low-sodium salt roasting-water leaching process. The effects of Na2CO3 addition, roasting temperature, and roasting time were investigated to determine the optimal roasting parameters. Subsequently, the effects of mechanical activation on the morphological and microstructural changes were characterized using a laser diffraction particle size analyzer, a micropore physisorption analyzer, scanning electron microscopy, energy dispersive spectrometry, and X-ray diffraction. The effects of mechanical activation on the extraction of vanadium and chromium were determined by leaching the roasted samples after varying activation times. The results indicated that mechanical activation decreased particle size, increased surface area, and enhanced the activity of the samples. The leaching results demonstrated that mechanical activation enhanced the leaching efficiency of vanadium by 5 %, reduced the optimum roasting temperature by 50 ℃, and slightly increased the leaching efficiency of chromium by 0.5–1 %.

Image-based simultaneous particle size distribution and concentration measurement of powder blend components with deep learning and machine vision

This work presents a system, where deep learning was used on images captured with a digital camera to simultaneously determine the API concentration and the particle size distribution (PSD) of two components of a powder blend. The blend consisted of acetylsalicylic acid (ASA) and calcium hydrogen phosphate (CHP), and the predicted API concentration was found corresponding with the HPLC measurements. The PSDs determined with the method corresponded with those measured with laser diffraction particle size analysis. This novel method provides fast and simple measurements and could be suitable for detecting segregation in the powder. By examining the powders discharged from a batch blender, the API concentrations at the top and bottom of the container could be measured, yielding information about the adequacy of the blending and improving the quality control of the manufacturing process.

Nanoencapsulation of α-mangostin using chitosan-oleic acid complexes: Evaluation of storage stability, in vitro release properties in simulated digestive environment, and bioaccessibility

The mangosteen fruit possesses a potent antioxidant known as α-mangostin. However, the poor aqueous solubility of α-mangostin limits its incorporation into food products, as well as its oral bioaccessibility in the human gastrointestinal tract. Therefore, we utilized electrostatic complexation between chitosan and oleic acid to encapsulate α-mangostin as a strategy to overcome these limitations. As a result, a homogeneous nanoparticle suspension (average particle diameter = 830 nm) was achieved, as verified by scanning transmission electron microscopy and laser diffraction particle size analysis. Importantly, the aqueous solubility of α-mangostin was significantly improved (>800 times), as examined using high-performance liquid chromatography, enabling its effective incorporation into foods and beverages. The nanoparticles were stable and conveniently stored in a dark vial at 4 °C for more than 2 weeks. In the simulated gastric environment, the pH sensitivity of the chitosan-oleic acid complexes enabled the α-mangostin to remain encapsulated in the gastric phase (pH 3) and to be released in the intestinal phase (pH 7) with a bioaccessibility percentage greater than 50%. Overall, the novel synthesized α-mangostin-encapsulated nanoparticles are beneficial for the design of functional foods with enhanced quality, gastrointestinal stability, and delivery.

Toward a tunable fabrication of multifunctional iron-aluminum spinels via solution combustion synthesis: The effects of fuel, heating mode, and Fe:Al precursor ratio

The solid solutions of iron and aluminum spinels (hercynite, maghemite, magnetite, and γ-alumina) are promising materials for emerging technologies such as solar thermochemical fuel production and clean dehydrogenation of fossil fuels. Solution combustion synthesis (SCS) is an attractive technique for the fabrication of these materials as it has been used for synthesis of many nanoscale oxides. However, the design space of SCS is large with many synthesis parameters affecting the properties of the combustion products. To optimize the SCS of these materials, it is important to determine which parameters yield the best properties. In the present work, FeAlOx nanocomposites were obtained by SCS using iron nitrate and aluminum nitrate as precursors and oxidizers. Two fuels (citric acid and glycine), three Fe:Al molar ratios (1:2, 1:1, and 2:1) in the precursors, and three heating modes (hotplate, muffle furnace, and microwave oven) were compared. The products were characterized by X-ray diffraction analysis, scanning electron microscopy, Brunauer-Emmett-Teller surface area analysis, and laser diffraction particle size analysis. The fuel used had the largest impact on the combustion behavior and hence the material properties. The high combustion temperature of glycine allowed for the formation of an FeAl2O4/Fe3O4 solid solution, while the lower-temperature combustion of citric acid yielded Al-substituted γ-Fe2O3 with high amorphous content. With citric acid, the specific surface area as high as 200 m2/g was achieved. The effect of Fe:Al precursor ratio was clearly seen in variations of the lattice parameter, which demonstrated the ability to tune the phase composition. The heating mode had minor effects on material properties, but some differences were observed. All products obtained by SCS in a microwave oven had low specific surface areas compared to those obtained with a hotplate and a muffle furnace.

Transglutaminase-crosslinked lesser mealworm protein isolate: A new milk fat substitute for high-quality probiotic set yogurts

Innovative non-fat probiotic set-style yogurts (NF-PSSYs) incorporated with lesser mealworm protein isolate (LMPI) crosslinked by microbial transglutaminase (MTGase) were optimized. The utilization of 4.65% w/w MTGase-crosslinked LMPI and 10.1 Log CFU/mL of Lactobacillus acidophilus La-5® resulted in maximum lightness, firmness, apparent viscosity, and probiotic survivability, and minimum syneresis with a desired acidity in NF-PSSYs. The fluorescence microscopy images and laser diffraction particle size analyses revealed small protein clusters with fine serum pores in the optimal yogurt gel. The sensory properties of optimal NF-PSSYs deteriorated slower than the control ones during refrigerated storage. A significantly lower loss rate in the DPPH inhibition activity, ferric-reducing power, and riboflavin content was found in optimal NF-PSSYs than in control yogurts. The attenuated total reflectance-Fourier transform infrared (ATR-FTIR) efficiently explored structure-activity relationships related to organoleptic and antioxidant properties. The in vitro simulated gastrointestinal digestion showed that the optimal yogurt had the highest digestive product content with fractions of molecular weight <15 kDa and proteolysis rate by pepsin and trypsin for 50 and 30 min, respectively. MTGase-crosslinked LMPI would be a promising fat replacer for manufacturing high-quality NF-PSSYs.

Spatiotemporal records of major historical events and human activities in river sediments: A coupled study of heavy metals distribution and lead isotopic dating

Thirty sediment samples (11 on the surface and 19 from a 55 cm core) collected in the Dadu River, upstream of the Yangtze River, China, were analyzed by ICP-MS and Laser diffraction particle size techniques to determine heavy metal spatial-temporal distribution and particle size characteristics, respectively. The intent was to clarify the impact of human activities such as Pb-Zn mining and exploration on the distribution of potentially toxic elements (As, Cd, Cr, Cu, Pb and Zn) in adjacent fluvial deposits. Moreover, 210Pb isotope dating was applied to study the historical variation and distribution of heavy metal pollution in a sedimentary profile in the middle section of the Dadu River. Results suggest that Cd concentration is notably high, exceeding by 16.3 times the soil background value in Sichuan Province, China, which can be intensified by Pb-Zn ore smelting. Surface sediments are mainly composed of silt, accounting for 79% on average, and relatively minor amounts of clay and sand. The fraction of clay in the downstream segments of the Dadu River is significantly higher than that upstream, indicating that the hydrodynamic force in the downstream region is relatively low compared with the upstream flow. Samples in the sedimentary profile, collected at 3 cm intervals, are mainly composed of silty sand, accounting for 75.6%, which comprehensively reflects the strong hydrodynamic force in this area. The results of 210Pb dating of these samples indicate three intervals of historical fluctuation in heavy metal concentrations: 1950–1966, 1988–1991 and 1996–2006, respectively, which coincide to significant historical events (the Cultural Revolution, the construction of Pubugou reservoir and local smelting activities, and the implementation of environmental protection policies). Enrichment factor (EF) values of all heavy metals in the profile began to increase after 1994, and relatively high EF values of Cr and Cd indicated a significant enrichment due to increasing anthropogenic activities during this period. Our study demonstrates that anthropogenic activities can be well recorded in sedimentary profiles and provide new insights to retrieving the history of human developments.

Transforming spent coffee grounds into a valuable resource for the enhancement of concrete strength

The decomposition of organic waste going to landfills produces methane gas, which is 21 times worse than CO2 in its global warming potential. Spent coffee grounds (SCG) are one type of organic waste that makes up a significant proportion of the organic waste going to landfills. Therefore, it becomes imperative to look for a recycling solution to transform this waste into a valuable resource. The concrete industry has the potential to contribute significantly to increasing the recycling rate of this waste material. However, due to its high organic content, it is unsuitable to be used directly in structural concrete. Therefore, this experimental project looks at pyrolysing this waste at different temperatures (350 and 500 °C) to identify its suitability in improving the physicochemical and mechanical properties of concrete. The raw and pyrolysed forms of SCG were used as a replacement of fine aggregates (FA; sand) at 5, 10, 15 and 20% volume replacement levels. X-ray fluorescence (XRF), Carbon, Hydrogen, Nitrogen, and Sulfur (CHNS) analysis, laser diffraction particle size analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and compressive strength tests were undertaken to investigate the properties of the raw material and their performance in the blended concrete composites. The results show that the leaching of organic compounds from the SCG hinders the hydration reaction of cement particles, thereby significantly hampering the compressive strength of SCG-blended concrete. However, pyrolysing the SCG at 350 °C led to a significant improvement in its material properties, which resulted in a 29.3% enhancement in the compressive strength of the composite concrete blended with coffee biochar.

Engineering artesunate-loaded micelles using spray drying for pulmonary drug delivery

Novel d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) micelles containing the anti-cancer drug artesunate (ART) were developed in a dry powder form for inhalation for the treatment of lung cancer. Targeted delivery to the lungs via inhalation presents a challenge, and the current study involved the development, characterization, and cytotoxicity determination of the dry powder formulations. TPGS micelles encapsulating ART were successfully prepared using thin-film hydration method, followed by the preparation of a dry powder formulation through spray-drying, which included lactose and leucine as carrier molecules. Characterization of the dry powder formulation using Sympatec laser diffraction particle size analyzer and a next generation impactor. The analysis showed a unimodal particle size distribution with a mean particle size of 3.27 μm and a fine particle fraction of 31%, respectively. Artesunate-loaded micelle dry powder formulation demonstrated higher cytotoxicity against the A549 adenocarcinomic human alveolar basal epithelial cell line when compared to currently used cancer therapies docetaxel and doxorubicin. Overall, this study demonstrates that spray-dried micelles containing artesunate have the potential to be used as a dry powder formulation for inhalation in the treatment of lung cancer.

A Composite Magnetosensitive Sorbent Based on the Expanded Graphite for the Clean-Up of Oil Spills: Synthesis and Structural Properties

Oil spills necessitate the development of effective methods for preventing their damaging effects on the environment. A number of physical, chemical, thermal, and biological methods are used to combat oil spills. Among them, sorption is considered to be efficient in removing thin oil films from water surfaces. Currently, there is an urgent need for simple methods of obtaining oil sorbents that include a magnetosensitive component to optimize the process of removing oil from the water surface. The purpose of the work is to obtain and research oil sorbents resistant to destruction, with increased bulk density and complex magnetosensitivity, based on thermally expanded graphite (TEG) with the inclusion of micro- and nano-particles of iron and its oxides. The structure and composition of the new composite material was characterized using scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffractometry, thermogravimetric analysis, and laser diffraction particle sizing. The composite sorbent comprised TEG with the inclusion of iron-containing magnetosensitive particles. Metal-carbon nanoparticles (MCN) were used as the magnetosensitive component; they had a magnetosensitive iron core covered with a carbon shell. We used two methods of synthesis, namely (i) mechanical mixing of the TEG flakes and MCN particles, and (ii) applying a thermal shock (microwave processing) to the mixture of graphite intercalated with sulphuric acid and micro- and nanoparticles of iron and iron oxides. In the first case, MCN particles were fixed on the faces, edges, and other surface defects of the TEG flakes due to intermolecular forces, coordinate bonds, and electrostatic interaction. The strong adhesion of magnetosensitive iron/iron oxide and TEG particles in the second case was due to the mutual dissolution of iron and carbon components during the thermal shock, which formed an interfacial layer in which iron carbide is present. The presence of magnetosensitive components in the structure of the proposed oil sorbents allows the use of magnetic separation for the localization and removal of oil spills, increases the density of sorbents, and, accordingly, leads to a decrease in windage while retaining the advantageous properties of thermally expanded graphite. According to the results of laboratory studies, the efficiency of removing oil from the water surface is not lower than 95–96%.

Quartz microfill dispersion optimisation

Introduction. One of the problems of developing new generation concrete is to ensure the rational granulometric composition of a mixture of cement and fine additives to ensure the densest packing of all particles of the cement system. In this regard, the paper considers the optimization of the dispersed structure of quartz filler, taking into account its specific surface area, concentration in the composition of the binder and water-solid ratio.Materials and methods. In the studies, Portland cement TSEM I 42.5 N (GOST 31108-2020) of ZAO Belgorod Cement and fine quartz were used. The compressive strength samples were tested on a PGM-100 MG4 laboratory press. The granulometric composition of the fillers was determined using Analysette 22 NanoTec plus laser diffraction particle size analyzer.Results. The conducted studies have allowed to determine that the optimal dosages of microdispersion filler are closely related to the specific surface area and the V/T of the mixture. It is shown that with an increase in the dispersion of quartz filler, a decrease in the range of optimal dosages is observed, which narrows with an increase in the water-solid ratio. The mechanisms of structure formation affecting the properties of dispersed-optimized cement systems are described. With the growth of the specific surface of the filler, the specific activity of the unit of the surface of the filled binder decreases, which is accompanied by a decrease in the number of crystallizationcoagulation bonds between the hydrate phases of cement.Conclusion. The experimental data obtained confirm that for a cement stone made of a mixed binder, the watersolid ratio is no less significant than the concentration of a mineral additive, therefore, a decrease in the V/T of mixed cements is a necessary condition for achieving a given strength.