Mixture Ratio Research Articles

Using tracer particle kinematics to sense particle size in rotating drums

Comminution is an energy intensive process. In SAG-mills, it is achieved by rotating a drum in which large metal balls crush ore particles. In-situ monitoring of particle size would be of considerable interest to optimize their operation. However, there is no established solution to measure particle size in such a harsh mechanical environment. We show here that the acceleration of the grinding media, which can be monitored using embedded accelerometers, can be used to sense the particle size and size distribution during operation. In DEM simulations, we find that a machine learning classifier is able to detect the size and distribution of small particles solely based on the knowledge of the acceleration of larger grinding media particles. Results show that this kinematic sensing is effective over a wide range of particle size ratios, size distribution, mixture ratio and mill charge. Beyond their potential applications in mineral processing, these results point out that the kinematics of large particles is affected by the size of the smaller particles, an observation which can help advance rheological models for bi-disperse granular flows.Graphical

High-temperature growth of Cu2O crystals via mist chemical vapor deposition on Si (111) substrates

Abstract Cuprous oxide (Cu2O) crystals were grown on Si(111) substrates at a high temperature of approximately 960 °C using mist chemical vapor deposition (mist-CVD) by varying the mist carrier gas parameters. The mist-CVD process has a potentially low environmental impact and low cost due to the absence of a vacuum system and the use of low-toxic raw materials. The as-grown crystals were evaluated using X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Based on these results, the mixture ratio of the mist carrier gas is significant for realizing Cu2O crystal growth. 


Optimizing Tris(2-Carboxyethyl)phosphine and Mercaptohexanol Concentrations for Thiolated Oligonucleotide Immobilization on Platinum Electrodes in Microfluidic Platforms.

In this study, we propose a strategy to explore the impact of the proportion of tris(2-carboxyethyl)phosphine (TCEP) and 6-mercaptohexanol (MCH) on the efficiency of oligonucleotide functionalization on PDMS microfluidic channels equipped with pairs of homemade microfabricated platinum microelectrodes. We identified an optimal concentration of these compounds that enables the effective orientation and distribution of probes, thereby facilitating subsequent target hybridization. The experiment included optimizing sample injection into microfluidic channels. We used TCEP as a reducing agent to help the DNA probes adhere to the channel electrode better. This stopped the formation of disulfide bonds during the probe immobilization step. We found the optimal TCEP/MCH mixture ratio (5 mM TCEP and 50 mM MCH), which led to a more uniform distribution and orientation of the DNA probes on the platinum electrode. These optimized conditions resulted in a more compact DNA monolayer and enhanced detection capabilities. The biosensor's performance was evaluated by the detection of the hybridization of complementary DNA sequences in the presence of equimolar Fe(CN)63-/Fe(CN)64-. The detection of the synthetic GP8 resistance gene is facilitated by a measurable decrease in the electron transfer rate, which is directly proportional to its concentration. Under the optimized conditions, the DNA biosensor showed excellent sensitivity (with a detection limit of 10-17 M) and high specificity when tested against noncomplementary DNA strands.

Calcium alginate reinforced zwitterionic double network hydrogel with mechanical robustness and antimicrobial activity for freshwater shrimp spoilage detection

Hydrogel indicators promise to monitor food spoilage, but their poor mechanics can cause defects in transport. Herein, a novel zwitterionic double network (DN) hydrogel was developed by polymerizing arylamide and sulfobetaine methacrylate in an alginate-Ca2+ system. This hydrogel exhibited enhanced mechanical properties, including a maximum 2087 % breaking elongation and 135 ± 12 kJ/m3 toughness, significantly outperforming the current zwitterionic DN hydrogels, which typically exhibit less than 1800 % breaking elongation, capable of supporting 150 g—136 times its own weight. Importantly, it also demonstrated excellent anti-fatigue and tear resistance, with a tearing energy of 2200 ± 180 J/m2. The abundant zwitterionic polymers, hydroxyl groups, and amino groups within hydrogel contribute to its strong adhesiveness to various substrates. Additionally, the hydrogel exhibited antimicrobial activity against E. coli and S. aureus. Furthermore, a pH/NH3 dual-sensitive hydrogel indicator, using phenol red, bromocresol purple, and their mixtures in ratios of 1:1, 1:2, and 2:1, was developed for monitoring shrimp freshness. The results showed that the hydrogel indicator with phenol red, effective at 4°C and 25°C, showed clear color changes (ΔE > 80) in response to spoilage and strong correlations between ΔE and TVB-N (R2 > 0.98) and pH (R2 > 0.97), surpassing the existing hydrogel indicators used for shrimp freshness monitoring, which generally have a correlation coefficient of only 0.86. This novel dual-responsive hydrogel, with excellent mechanical performance and TVB-N sensitivity, is suitable for real-time freshness monitoring in intelligent packaging.

Development and field test of Red mud-Fly Ash Geopolymer pile (RFP)

Red mud is an industrial solid waste obtained from the extraction of alumina from bauxite. In order to study the resource utilization of red mud and improve its comprehensive utilization rate, based on the principle of geological polymers, red mud based geological polymers are prepared using raw materials such as red mud, fly ash, blast furnace slag powder, sand, stone, and alkaline solution as pile materials. Through lab experiments, the ratio of red mud and fly ash geopolymer mixtures that can be used for underwater injection and pumping has been obtained; Through on-site experiments, the complete construction process and the bearing characteristics of red mud-fly ash geopolymer piles (RFP) was studied. Environmental impact assessments were conducted by monitoring the changes in water quality around the RFP. The research results laid the foundation for the engineering application of RFP piles. It was found that: (1) At a liquid-solid ratio of 0.55, the geopolymer mixture of red mud: fly ash: sand: crushed stone: GGBS=(1:2:2:4.94:0.1) has good workability. The geopolymer with this mix ratio can meet the performance requirements of pumping and underwater perfusion, the slump can be controlled between 220-225mm, and the strength after 28 days of room temperature curing is 13.9MPa. (2) Developed a complete set of construction techniques for RFP, including drying, grinding and sieving of red mud, preparation of alkaline activator solution, sequence of material mixing, and related processes for pile drilling, placement of conduits, and conduit method grouting. (3) The load test results show that in a silty clay foundation, the ultimate vertical compressive bearing capacity of a single RFP with a pile length of 10.0 meters and a pile diameter of 520mm is 753kN. When the pile spacing is 1.5m, the bearing capacity of single-pile composite foundation is 240kPa. The Q-S curve and the stress distribution curve of the pile indicate that its load transfer characteristics are consistent with those of ordinary concrete piles. The results of the core sampling test on the pile body show that the core sample taken from the 10m pile is relatively complete, the rate of core recovery reaches over 99%,it shows that the pile body is intact. The compressive strength experiment shows that the strength of core samples at different depths is above 10MPa,and up to 19.5MPa. (4) The continuous water quality monitoring results for 5 months indicate that the implementation of RFP has not cause significant adverse effects on the quality of surrounding water bodies.

Research on gradual optimization of slurry mixture ratio for shield tunnel backfill grouting based on fuzzy mathematics

Research on gradual optimization of slurry mixture ratio for shield tunnel backfill grouting based on fuzzy mathematics

Influence of water-repellent admixtures ( Sitren and Stearate materials) on the microstructure and mechanical performance of conventional Portland cement paste and mortar

The longevity of mortar and concrete structures can be compromised by the absorption of water and other fluids, leading to deterioration and aesthetic issues. To address this, water-repellent admixtures are employed to enhance the service life of mortar and concrete components by improving their mechanical and microstructural characteristics. This study focus on the effects of incorporating Sitren P 750 and various stearate materials (calcium, zinc, aluminum, and barium) as admixtures with ordinary Portland cement at mortar and paste dosages of 0.5%, 1.0%, and 1.5% of the cement content. We found that mortars with water-repellent admixtures exhibited competitive mechanical properties at all curing ages. Additionally, the study confirmed the contribution of these admixtures to the production of hydration products and the structural development of the mortars, as investigated through scanning electron microscopy, thermogravimetric–derivative thermogravimetric, and X-ray diffraction analyses. Despite alterations in several physical properties and hydration kinetics due to the water-repellent compounds and their dosages, all admixtures provided effective water-repellent protection. This was further corroborated by water contact angle tests and the measurement of the capillary water absorption coefficient for all samples. Identifying the optimal mixture ratio for construction technology and effectively incorporating repellence features is a crucial aspect of this research.

Low corrosive dual desiccant air conditioning: Antimicrobial activity, performance characteristics, and economic valuation with traditional VCRS

Liquid desiccant dehumidification systems (LDDS) serve as an energy-efficient alternative to conventional vapor compression refrigeration (VCR) systems, providing enhanced control over both temperature and humidity levels. However, the broader implementation of LDDS is limited due to the corrosive effects of the liquid desiccants on metal components. In response, this study introduces an economical blend of potassium formate (HCOOK) and magnesium chloride (MgCl2) designed to minimize corrosion while maintaining energy efficiency and performance. Selection of mixture ratio and solution concentration and determination of thermo-physical properties were conducted by initial lab-scale tests. Significant bactericidal effects against E. coli and S. Aureus were observed. The feasibility and effectiveness of the developed solution were experimentally tested by a comparative investigation in a large-scale solar-integrated liquid desiccant dehumidification system against standard HCOOK (63.5 wt%). The cyclic performance of the novel desiccant solution was examined under varying operational conditions for tropical climates. Results demonstrated that the corrosion levels of the new mixture are comparable to those observed with a standard 63.5 wt% HCOOK solution, while the dehumidification efficiency showed significant improvements, with moisture removal and effectiveness enhanced by 8.7–14.3 % and 5.8–15.2 %, respectively. Significant regeneration occurred between 45 °C and 55 °C. Regeneration efficiency improved by a maximum of 12.5 % relative to the standard HCOOK solution. Notably, the deployment of a solar-assisted regeneration system led to energy cost reductions by 22.8 % compared to traditional VCR systems, achieving a return on investment within 1.8 years.

Enhancing the bonding reliability of titanium alloy / CFRTP hybrid joint by directionally inducing high-density covalent bond and secondary interaction via functional diblock copolymer

The hybrid joint of titanium alloy (Ti–6Al–4V)/carbon fibers reinforced thermoplastic (CFRTP) has gained high interest from the industry due to lightweight. However, the bonding reliability of fabricated joints is relatively low due to the confined mechanical interlocking and weak interfacial chemical interactions, which limits its application for engineering. Herein, the novel functional poly glycidyl methacrylate-b-poly methacryloxy propyl trimethoxyl silane (PGMA-b-PMPTS) diblock copolymers were synthesized and introduced at the contact interface of Ti–6Al–4V/carbon fibers reinforced polyether-ether-ketone joints for enhancing the bonding reliability by directional induction of chemical interactions. Fourier-transform infrared spectroscopy (FT-IR) analysis and density functional theory (DFT) simulation calculation proved that both the Si–O–Ti covalent bonds and secondary interactions were successfully induced directionally at the bonding interface. The tensile-shear strength and bending strength were thus significantly improved by 341 % to 40.17 MPa and 152 % to 238.53 MPa compared with that of 9.09 MPa and 94.53 MPa in pretreated case. The bonding reliability improved gradually with the increase of molecular weight and molecular weight ratios between functional groups of PGMA-b-PMPTS diblock copolymers. The adhesion ratio of resin-carbon fibers mixture on failure surface increased to 89.6 % after the modification with synthesized PGMA-b-PMPTS diblock copolymers, which further verified the feasibility of promoting bonding strength of Ti–6Al–4V/CFRTP by inducing the high-density interfacial interactions directionally. Current work exhibits a simple yet attractive interfacial modification strategy to achieve high-reliability hybrid joints between metal and thermoplastics.

A sensitive and reliable method for the quantitative determination of hydrogen peroxide produced by microalgae cells.

One of the reactive forms of oxygen is hydrogen peroxide (H2O2), which has been investigated as a key component of growth processes and stress responses. Different methods for the determination of H2O2 production by animal and bacterial cells exist; however, its detection in algal cell cultures is more complicated due to the presence of photosynthetic pigments in the cells and the complex structure of cell walls. Considering these issues, a reliable, quick, and simple method for H2O2 detection is needed in phycological research. The aim of this methodological study was to optimize an Amplex UltraRed method for the fluorometric detection of H2O2 produced by microalgae cells, using a wild-type strain of Chlamydomonas reinhardtii as a model. The results showed that (i) potassium phosphate is the most suitable reaction buffer for this method, (ii) a 560 nm wavelength variant is the most appropriate as the excitation wavelength for fluorescence spectra measurement, (iii) a 50:50 ratio for the reaction mixture to sample was the most suitable, (iv) the fluorescence signal was significantly influenced by the density of the microalgae biomass, and (v) sample fortification with H2O2 allowed for an increase of the method's reliability and repeatability. The proposed protocol of the Amplex UltraRed method for the fluorometric detection of H2O2 produced by microalgae cells can yield a sensitive and accurate determination of the content of the test compound, minimizing measurement errors, eliminating chlorophyll autofluorescence problem, and compensating for the matrix effect. This method can be applied to the study of other microalgae species.

Effect of Process Parameters on Nano-Microparticle Formation During Supercritical Antisolvent Process Using Mixed Solvent: Application for Enhanced Dissolution and Oral Bioavailability of Telmisartan Through Particle-Size Control Based on Experimental Design

Background/Objectives: This study investigates the impact of supercritical antisolvent (SAS) process parameters on the particle formation of telmisartan, a poorly water-soluble drug. Methods: A fractional factorial design was employed to examine the influence of the SAS process parameters, including solvent ratio, drug solution concentration, temperature, pressure, injection rate of drug solution, and CO₂ flow rate, on particle formation. Solid-state characterizations of the SAS process particles using XRD and FT-IR confirmed their amorphous nature. The effect of particle size on the kinetic solubility, dissolution, and oral bioavailability of telmisartan was also assessed. Results: Using a mixture of dichloromethane and methanol, telmisartan amorphous nano-microparticles with sizes between 200 and 2000 nm were produced. The key parameters, particularly drug solution concentration and temperature, significantly affected the particle size. Interestingly, the ratio of the solvent mixture also had a significant effect on the particle morphology. Further experiments were performed to determine the conditions for preparing telmisartan amorphous nano-microparticles with various sizes by controlling the solvent mixture ratio and the concentration of the drug solution. It was revealed that a reduction in the amorphous particle size enhanced both the kinetic solubility and dissolution rates, leading to a significantly increased in vivo oral bioavailability in rats compared to unprocessed telmisartan. Conclusions: These findings suggest that SAS processing, utilizing adjustments of process parameters, offers an effective strategy for enhancing the bioavailability of poorly soluble drugs by generating amorphous spherical nano-microparticles with optimized particle size.

Experimental investigation of damping ratio of sand-laponite and sand-bentonite mixtures using one-dimensional bender elements

Damping ratio and dynamic shear modulus are fundamental parameters for assessing the seismic response of geotechnical structures such as retaining walls, dams, tunnels, foundations, landfill covers, and embankments. Numerous seismic wave sources can substantially impact the stability and integrity of geotechnical structures, influencing design choices and the implementation of alternative solutions. In this study, the damping ratio of sand mixed with small quantities of laponite was determined by an experimental set-up using bender elements meticulously constructed for this study. Comparative tests were conducted with pure sand (i.e., control test) and sand mixed with bentonite to evaluate the effects of two types of nanoparticles. The results revealed that the damping ratio (ξ) of pure sand was approximately 7.48 %, which is generally compatible with values reported in the literature, taking into account the variations of sand and errors associated with laboratory equipment and electronic devices. Over time, the damping ratio of pure sand gradually decreased, reaching equilibrium at 0.99 % after 3–4 days of continuous shaking. The highest observed damping ratios for sand-laponite mixtures were 59 %, 69.7 %, and 98.6 % for sand+1 % laponite, sand+2 % laponite, and sand+3 % laponite, respectively. After reaching the peak, the damping ratio gradually decreased to equilibrium at 11 %, 16 %, and 19.4 %, respectively. The higher damping values for sand-laponite specimens reflect a viscous damping contribution from the presence of laponite at sand grain contacts, with higher laponite content resulting in increased damping. In comparison, the peak damping ratios for sand-bentonite mixtures were 21.9 %, 42.7 %, and 67.9 % for sand+1 %, +2 %, and +3 % bentonite, respectively. The findings highlight the potential of laponite to enhance the damping capacity of sands, which could be valuable for seismic design applications requiring improved energy dissipation.

Optimizing multiple ecosystem services in Eucalyptus plantations: Dual effects of intercropping and restoration

Mixed plantations of Eucalyptus with native tree species can effectively improve forest ecosystem services. However, the long-term effects and ratios of Eucalyptus-native tree species mixture on plant diversity in different plant layer, multiple ecosystem services, multiservice and the underlying mechanisms remain unclear. To fill these gaps, a four-level intercropping gradient of Eucalyptus urophylla planted with eight native tree species (NS) was set up (i.e., 20%NS, 30%NS, 40%NS, 50%NS), monitored and compared with a monoculture E. urophylla plantation (EU) and a randomly mixed plantation (98%NS) in southern China. We calculated the multiple ecosystem services of the plantation and the multidimensional diversity (taxonomic diversity (TD), functional diversity (FD), and phylogenetic diversity (PD)) of different plant layers. The results showed that the long-term (13–15a) and short-term (1a) plantation communities were significantly different in multidimensional diversity in all three vertical plant layers. In the long-term, intercropping with more than 20% native trees significantly increased the multidimensional diversity in the tree layer, but not the shrub and herb layers, compared to the EU. Intercropping with 50% native trees significantly promoted biodiversity conservation service, ecosystem multiservice and synergistic relationships among ecosystem services over a decade. Both initial mixing ratio and naturally restored multidimensional diversity in shrub and herb layers influenced tree layer's multidimensional diversity, contributing to long-term multiple ecosystem services of mixed Eucalyptus-native tree species plantations. Our results highlighted the risk of applying short-term based diversity results in long-term strategy making for E. urophylla plantation, quantitatively explored the high explanatory power of plant functional and phylogenetic diversities on multiservice, and expanded understanding of the mechanisms of the triad, biodiversity-ecosystem service-ecosystem stability. To practice, intercropping 50% native trees was recommend for long-term optimizing multiservice restoration, including but not limited to biodiversity conservation, and the syngeneic development among ecosystem services of Eucalyptus plantations.

Experimental and machine learning insights on heat transfer and friction factor analysis of novel hybrid nanofluids subjected to constant heat flux at various mixture ratios

This study explores the combined effects of aluminum oxide (Al₂O₃)/graphene oxide (GO) hybrid nanofluids in 50:50 and 80:20 ratios, offering a notable improvement over conventional Al₂O₃ or GO nanofluids. It delivers a thorough comparison of thermophysical properties such as thermal conductivity and viscosity and heat transfer performance across water, Al₂O₃ nanofluids, and the Al₂O₃/GO hybrids. Nanofluids at 0.1–0.5 % volume concentrations were tested in a horizontal circular pipe under constant heat flux and turbulent flow with an inlet temperature of 60 °C. The maximum Nu enhancements of 64, 56 and 41 % were noted for Al₂O₃/GO (50:50), Al₂O₃/GO (80:20), and Al₂O₃ nanofluids, respectively at 0.5 vol%, compared to water. The maximum pressure drop of Al2O3/GO (50:50) nanofluid is 5.64 and 8.3 % greater than that of Al2O3/GO (80:20) and Al2O3 nanofluid, respectively at 0.5 vol%. The peak thermal performance index of 1.56, 1.48, and 1.33 is observed for Al₂O₃/GO (50:50), Al₂O₃/GO (80:20), and Al₂O₃ nanofluids. The integration of a multi-layer perceptron artificial neural network further enhances accuracy in predicting thermal performance, surpassing the precision of conventional empirical models. The adopted model showed excellent predictive accuracy, with correlation coefficients of 0.98493 in training, 0.9837 in validation, and 0.98698 in testing.

Mixture proportion optimization and durability evaluation of rejuvenating composite seal

Composite seal (CS) is effective in restoring pavement surface function and prolonging the service life, employing a double-layer structure composed of micro-surfacing and chip seal. Rejuvenating composite seal (RCS) applying rejuvenating agents to the chip seal is dedicated to revitalizing the aged asphalt of the original pavement surface. However, limited studies have focused on enhancing interlayer and temperature performance through optimizing mixture ratios. In this study, a modified emulsified asphalt with self-developed rejuvenating agent was applied, and the orthogonal test considering interlayer shear resistance and high temperature stability was conducted for initially mixture proportion of RCS, then the preliminary ratio was optimized. The proportion for micro-surfacing was determined by mixing test, wet track abrasion test, and loaded wheel sticking sand test. Simultaneously, the recommended asphalt spraying amount of rejuvenating chip seal was determined by utilizing accelerated loading abrasion test. In view of the abrasion resistance, interlayer adhesion, and cracking resistance, the coupled effects of aggregate size and paving rate of rejuvenating chip seal were studied. Long-term wet track abrasion test, freeze-thaw cycle test, and UV aging test were conducted to evaluate the durability. The results show that the asphalt-aggregate ratio of micro-surfacing is 7.1 %. For 4.75 mm or 7 mm rejuvenating chip seal, the recommended asphalt spraying amount is 1.5 kg/m2 or 1.6 kg/m2, and the range of paving rate is 60 %–70 %. For 9.5 mm or 13.2 mm rejuvenating chip seal, the results are 1.7 kg/m2 or 1.8 kg/m2, and 80 %–90 %, respectively. Under the conditions, RCS has better interlayer shear resistance and temperature performance, which can improve durability.

Isotope-dependent site occupation of hydrogen in epitaxial titanium hydride nanofilms

Hydrogen, the smallest and lightest element, readily permeates a variety of materials and modulates their physical properties. Identification of the hydrogen lattice location and its amount in crystals is key to understanding and controlling the hydrogen-induced properties. Combining nuclear reaction analysis (NRA) with the ion channeling technique, we experimentally determined the locations of H and D in epitaxial nanofilms of titanium hydrides from the analysis of the two-dimensional angular mappings of NRA yields. Here we show that 11 at% of H are located at the octahedral site with the remaining H atoms in the tetrahedral site. Density functional theory calculations revealed that the structures with the partial octahedral site occupation are stabilized by the Fermi level shift and Jahn-Teller effect induced by hydrogen. In contrast, D was found to solely occupy the tetrahedral site owing to the mass effect on the zero-point vibrational energy. These findings suggest that site occupation of hydrogen can be controlled by changing the isotope mixture ratio, which leads to promising manifestation of novel hydrogen-related phenomena.

Performance Evaluation and Optimization of Binder-Toner and Mixing Efficiency Ratios in an E-Waste Toner-Modified Composite Mixture Using Response Surface Methodology

E-waste toner (EWT), which is produced in large quantities by modern industries, has the potential to be utilized as a bitumen modifier to improve engineering properties and save costs. The current study focuses on exploring the optimization of EWT content to identify the most optimal proportions for achieving desirable levels of mechanical properties. This study also examined the effects of E-waste toner contents ranging from 0% to 30% on the fresh consistency of toner-modified and unmodified binder. The study utilized a central composite design (CCD) together with the response surface methodology (RSM) to optimize the mix design variables, specifically the binder-toner ratio (BT) and mixing efficiency ratio (MER). The objective of this study was to examine the combined effects of these variables on the mechanical characteristics of EWT-modified asphalt mixtures. The mechanical responses were obtained through the performance of four responses such as Marshall stability (MS), Marshall flow (MF), indirect tensile strength (ITS), and stiffness tests. The findings suggest that the combined interaction of BT and MER ratios has an impact on their mechanical characteristics. However, the BT ratios had a significant impact on the volumetric attributes compared to MER. The RSM-based prediction models had an R-square over 0.86 across each response. This demonstrates that the inclusion of BT and MER ratios were accountable for a minimum of 86% of the alterations in the mechanical characteristics of EWT-modified asphalt. The multi-objective optimization analysis determined that the optimal proportions for the EWT-modified asphalt, in order to obtain the ideal consistency, were 0.249 ratio of BT and 1.63 ratio of MER with a desirability value of 0.97. Overall, it was found that RSM is a reliable technique for precisely forecasting the mechanical properties of EWT-modified asphalt, including BT and MER ratios.

Study of nifedipine solubility in physical mixtures and solid dispersions

Introduction. Poor aqueous solubility significantly hinders the bioavailability of numerous orally administered drugs. Nifedipine, a widely-used cardiovascular agent, is categorized as practically insoluble according to pharmacopoeias, thus presenting a significant challenge in formulation development. This study investigates the potential of solid dispersion (SD) technology and physical mixtures to improve the dissolution profile of nifedipine.Aim. Development of a technological method for increasing the solubility of nifedipine by developing physical mixtures and SD with the aim of creating a dosage form with improved properties.Materials and methods. Nifedipine, methanol, nifedipine standard samples, potassium dihydrogen phosphate, sodium heptanesulfonate, phosphoric acid (85 %), purified water, and pvp K-30. Solubility studies were performed by HPLC using three objects: nifedipine, a physical mixture (PM), and SD of nifedipine with PVP K-30. The study assessed the effect of different ratios (nifedipine : PVP K-30) in the physical mixture and SD on nifedipine solubility. Fourier transform infrared spectroscopy (IR spectroscopy) and powder X-ray diffractometry were used to characterize the samples.Results and discussion. A notable increase in nifedipine solubility was observed in both PM3 (1 : 3 nifedipine : PVP K-30) and SD3 (1 : 3 nifedipine : PVP K-30). PM3 exhibited a solubility of 9.70 %, while SD3 demonstrated a remarkable enhancement to 32.07 % compared to the pure nifedipine (0.24 %). FTIR analysis did not reveal significant interactions between nifedipine and PVP K-30. PXRD results confirmed the transition of nifedipine from a crystalline to amorphous form within the hydrophilic PVP K-30 matrix, contributing to the observed solubility enhancement.Conclusion. The study highlights the effectiveness of SD technology in significantly improving nifedipine solubility and potential bioavailability. The 134-fold increase in solubility achieved with SD3 at a 1 : 3 ratio demonstrates the significant potential of this approach for enhancing the pharmacokinetic properties of poorly soluble drugs. This research opens up new avenues for developing innovative formulations with improved dissolution characteristics and potentially enhanced therapeutic efficacy.

Change in the Chemical State of Phosphorus Sulfide Molecules Inside Single‐Walled Carbon Nanotubes

This article presents the first experiments on filling single‐walled carbon nanotubes (SWCNTs) with the phosphorus sulfides P4S3 and P4S10 using the ampoule method. Transmission electron microscopy examination reveals the encapsulation of phosphorus and sulfur species inside the cavities of SWCNTs without the formation of any regular structures. X‐ray photoelectron spectroscopy observes different oxidation states of P and S atoms, depending on the P/S ratio in the initial mixture used to fill the nanotubes. The Raman signals associated with the encapsulated species are low in intensity, and the vibrational modes are shifted and broadened as compared to those in crystalline P4S3 and P4S10. The proposed models for the arrangement of sulfur and phosphorus inside SWCNTs suggest the formation of 1D amorphous glassy phosphorus sulfides with stoichiometric ratios close to those of elemental phosphorus and sulfur in the initial mixtures.

Thermophysical Properties of Silicon Oxide Nanoparticles in Water and Ethylene Glycol–Water Dispersions

Measurements of transmission as well as thermophysical properties have been carried out for different concentrations of SiO2 nanoparticles (0, 1, 2, 5, 10, and 20 wt.%) in pure water (W) and ethylene glycol–water mixture (EG/W) in a weight ratio of 25/75, from 298 to 323 K at 100 kPa. In particular, the density, specific heat capacity, and thermal diffusivity are measured by a density meter, differential scanning calorimetry, and the laser flash method. In the case of 20 wt.% SiO2, transmission in the visible range is reduced by 9.3%. Simultaneously, the density rises linearly to 12.3% (in W) and 11.3% (in EG/W). The specific heat capacity decreases to 15.9% (in W) and 17.3% (in EG/W), while the thermal diffusivity rises to 16.4% (in W) and 20.4% (in EG/W). While the density measurements are in very good agreement with the literature, the measured values of the specific heat capacity deviate more than 5%, especially for concentrations below 5 wt.% SiO2. Moreover, it is shown that the thermal conductivity increases less for fluids in small gaps compared to other authors, which could be due to the suppression of the Brownian motion. Based on the measurement results, temperature- and concentration-dependent correlations for the investigated thermophysical properties are developed using two adjustable parameters. In general, these correlations show deviations of less than 4% from the experimental results, which will help to fill the gaps in the variation of experimental results due to size, SiO2 nanofluid production, and different measurement devices, and thus optimize solar thermal applications with SiO2 nanofluid.