Search Results (117)

Oral delivery of hydrophobic compounds remains challenging due to their poor aqueous solubility and the potential toxicity associated with conventional surfactant-based emulsions. To address these issues, we present a surfactant-free encapsulation strategy using electrosprayed alginate hydrogel beads for the stable and controlled delivery of hydrophobic oils. Hydrophobic compounds were dispersed in high-viscosity alginate solutions without surfactants via ultrasonication, forming kinetically stable oil-in-water dispersions. These mixtures were electrosprayed into calcium chloride baths, yielding monodisperse hydrogel beads. Higher alginate concentrations improved droplet sphericity and suppressed phase separation by enhancing matrix viscosity. The resulting beads exhibited stimuli-responsive degradation and controlled release behavior in response to physiological ionic strength. Dense alginate networks delayed ion exchange and prolonged structural integrity, while elevated external ionic conditions triggered rapid disintegration and immediate payload release. This simple and scalable system offers a biocompatible platform for the oral delivery of lipophilic active compounds without the need for surfactants or complex fabrication steps. Full article

A method to prepare free-standing, few-micron-thick films from a dental photopolymer resin, namely UDMA-TEGDMA in a 3:1 weight ratio, doped with gold nanorods, is presented. The method is based on a sandwich structure consisting of a 4 μm thick PVA sacrificial layer, the Au-nanorod/UDMA-TEGDMA nanocomposite layer, and glycerol, all spin-coated sequentially onto a glass slide. Glycerol serves as a cover layer to shut out oxygen during photopolymerization, while the water-soluble PVA enables the subsequent detachment of the nanocomposite film by simple immersion into a liquid bath. Layer thicknesses were controlled by profilometry, while the presence of homogeneously dispersed gold nanorods was confirmed by optical spectroscopy and dark-field optical microscopy. A total of five similar spin-coating scenarios were tested, out of which two approaches produced positive results, with final nanocomposite layer thicknesses in the 2.5–4 μm range, which is smaller than the usual thickness of the oxygen inhibition layer (OIL) commonly present in these types of resins. Optimization of these technological processes and parameters to control film thickness and consistency is discussed in detail. Full article

The microencapsulation of bioactive compounds from rapeseed oil using sodium alginate, in the presence and absence of an ultrasonic (US) field, is reported. A Box–Behnken experimental design is used to investigate the influence of process parameters on the microencapsulation yield; then, the response surface methodology is applied, to find their values ensuring its optimum yield. The operating parameters investigated are the ratio of sodium alginate to rapeseed oil, the microencapsulation time and the concentration of the calcium chloride solution. The US bath was used at its nominal power, and the microencapsulation temperature was kept at 20 °C, with a thermostat, for all experiments. A detailed study on the comparison of the two microencapsulation techniques (in the presence and absence of the US field) was carried out. Good results were obtained in the presence of the US field for optimal conditions, when the microencapsulation yield was 90.25 ± 0.02%, higher than the microencapsulation process performed in the absence of the US field, 87.11 ± 0.02%. The results also showed that the use of the US field (optimal conditions) led to an increase in encapsulation efficiency, total phenolic content and antioxidant capacity (76.56 ± 0.02%, 324.85 ± 0.01 mg GAE/g and 57.05 ± 0.12 mg/mL). The physicochemical description of microcapsules was performed using modern characterization methods. These results indicate that by increasing the microencapsulation yield of bioactive compounds through sonication, the process aims to achieve a uniform size distribution of microcapsules. Full article

Oil-in-water emulsions (O/W emulsions) are generally used to lubricate the cold rolling process of low-carbon steel. In addition to the obvious advantages of efficient lubrication and cooling of the process, there are also some disadvantages, mainly related to emulsion bath maintenance, subsequent production steps and waste disposal. In some application areas, Oil-Free Lubricants (OFL’s) have been shown to be at least equally effective in decreasing friction and wear as conventional oil-based lubricants, while resulting in benefits related to waste disposal. In 2023, a project named “Transfer of aqueous oil free lubricants into steel cold rolling practice” (acronym ‘RollOilFreeII’) began, with it receiving funding from the Research Fund for Coal and Steel (RFCS). This project aims at an industrial application of Oil-Free Lubricants in the steel cold rolling process. The project builds on the work of the ‘RollOilFree’ project (also carried out in the RFCS-framework). This article briefly recapitulates the findings in the RollOilFree project and describes the objectives, benefits, activities and first results of the RollOilFreeII project. Notably, a pilot mill trial at high speed has been carried out, showing a good performance of the investigated OFLs. Back-calculated friction values were equal to, or even slightly lower than, reference O/W emulsions. The strip cleanliness with OFLs is much better than it is with the reference O/W emulsions. Only for a very thin product, as is the case in tinplate rolling, does the direct application of a conventional O/W dispersion (a high-particle-sized O/W emulsion) give a better performance than the investigated OFLs. Further development of OFLs should focus on this aspect. Full article

Excessive water produced in oil reservoirs reduces oil recovery and increases the cost of water treatment. Conventional water control methods use synthetic polymer gels like PAM-PEI, which are sensitive to harsh reservoir conditions. This study investigates the use of cellulose nanofibers (CNF) to enhance polymer gels for oilfield water control under various temperatures, salinities, and pH conditions. Polymer gels were prepared by combining PAM and PEI with CNF concentrations of 1–4 wt% in deionized water. Salinity effects were studied by adding NaCl (1.5–2.5 g), while pH effects were assessed under acidic (pH 2–3), neutral, and alkaline (pH 13–14) conditions. The mixtures were stirred, homogenized, and subjected to thermal treatment in a water bath oven at temperatures ranging from 70 °C to 90 °C for gel formation. Gelation time was determined by the Sydansk gel code, and gel strength was assessed through storage modulus (G′) and loss modulus (G″) from oscillatory rheometry tests. Results show that lower temperatures increase gelation time, with higher CNF concentrations needed to elongate gelation at higher temperatures. At 30,000 ppm NaCl, gelation time decreases with increasing CNF, while at 50,000 ppm NaCl, it increases. Extreme pH conditions (pH 2–3 and pH 13–14) lead to longer gelation times with decreasing CNF concentration. While high salinity and extreme pH reduce gel strength, the addition of CNF enhances it, though this effect is minimal beyond 2–3 wt%. These findings suggest that CNF can improve the performance of polymer gels under challenging reservoir conditions. Full article

This study reports a new and simple method for applying and dispersing carbon nanotubes (CNTs) in polymers, without prior chemical treatment or functionalization. The process is innovative, fast, and carried out at room temperature, without the need for specialized labor, just using the cavitation energy of ultrasonic bath to enhance properties such as impermeability and high electrical conductivity. The time of the dispersion process is 30 min and diverse concentrations of carbon nanotubes (0.1%, 0.5%, and 2%) in the total road marking paint mass were employed. This study also demonstrates the effect of the nanostructured paint applied to roadways, based on the macro texture (sand test) and in the microstructure pattern obtained (British Pendulum Tester). In addition, this study demonstrates that achieving an effective dispersion of CNTs in road marking paints produces a conductive and thermally stable paint, which also serves as a promising waterproof layer, expanding its applications in road maintenance, for example. The results from the sample with a 2% CNT content revealed enhancements in polymer conductivity in contrast to the reference, coupled with increases of up to 20% in impermeability to water and glycerin. No alteration in wettability is noted in automotive oil upon the introduction of CNTs, implying that nanostructured road paints could augment safety, traffic flow efficiency, and the environmental sustainability of future transport systems. Full article

This study aimed to develop a supersaturated liquid formulation (SSLF) to enhance the solubility and dissolution of pazopanib hydrochloride (PZH). SSLFs were prepared by a simple stirring method in a heated silicon oil bath (70 °C). PZH showed highly pH-dependent solubility (pH 1.2 > water >> pH 4.0 and pH 6.8) at 37 °C. The SSLF containing glycerol and polyvinylpyrrolidone K30 (PVP K30) increased PZH dispersion solubility (273.66 ± 48.91 μg/mL) at pH 6.8 by more than 50-fold compared with that of glycerol alone (<5 μg/mL), and the PZH precipitate particle size was considerably small (<100 nm). Moreover, the dispersion solubility of PZH from SSLF containing additional propylene glycol (PG) increased to 364.41 ± 2.47 μg/mL. The optimized SSLF10 (PZH/glycerol/PG/PVP K30 = 10/50/20/20, w/w) exhibited a high dissolution rate at pH 4.0 (>90%) and 6.8 (>55%) until 360 min, whereas PZH powder and PZH glycerol solution showed pH-dependent, low dissolution rates (<10%) under similar conditions. The supersaturation ratio of SSLF10 was very high at 29.88 and 18.36 at pH 6.8 and 4.0, respectively, indicating a stable PZH supersaturation solution. In the transmission electron microscopy analysis, PVP K30 and PG in SSLF10 synergistically suppressed PZH precipitation and recrystallization with small amorphous particles (<200 nm). Therefore, SSLF10 would be a promising formulation with enhanced solubility and dissolution rates regardless of medium pH. Full article

The palm oil industry (POI) generates significant amounts of waste, including calcium carbonate (CaCO₃) from the clay bath system used for the separation of palm kernels from shells. This CaCO₃ waste is often discarded, leading to environmental issues. However, the CaCO₃ can potentially be reused in the clay bath separation process to improve efficiency and reduce waste. To obtain PKO, the kernel is separated from the palm shell using a clay bath unit, where natural CaCO₃ acts as a decanting agent and adsorbent. This wet separation method, involving a mixture of water and CaCO₃ with a density of 1.12 g/mL, generates substantial amounts of saturated CaCO₃ waste that is often discarded into the environment. Therefore, this research aimed to regenerate oil-bound CaCO₃ waste for reuse as a decanter and adsorbent. Three treatments were tested, with CaCO₃ waste-to-water ratios of 1:1, 1:3, and 1:6, under varying pH levels (8, 10, 11, 12) and temperatures (28 °C, 80 °C, 100 °C). The regeneration process was conducted in an open reactor at 450 rpm with a volume of 0.0054 m³, followed by drying and grinding the waste for analysis. The results showed approximately 75.75% oil removal and CaCO₃ regeneration rates between 94.50% and 99.26%, with an increase in density from 1.687 g/mL to 2.467 g/mL. The efficiency of reusing regenerated CaCO₃ waste is 96.87%. When mixed with 25% natural CaCO₃, the efficiency increases to 99.24%. Additionally, a mixture of 50% regenerated CaCO₃ waste and 50% natural CaCO₃ achieves an average efficiency of 99.46% over five consecutive feed additions. This showed that the reuse of CaCO₃ waste regeneration results for the separation of palm shells and kernels has a high potential for application. These findings suggest that regenerated CaCO₃ waste can be effectively reused, offering a sustainable solution for palm oil mills. Full article

This study investigates the power losses of rolling element bearings (REBs) lubricated using an oil bath. Experimental tests conducted on two different deep-groove ball bearings (DGBBs) provide valuable insights into the behaviour of DGBBs under different oil levels, generating essential data for developing accurate models of power losses. Observations of the oil bath dynamics reveal the formation of an oil ring at high oil levels, as observed for planetary gear trains, leading to modifications in the oil flow behaviour. The experiments demonstrate that oil bath lubrication generates power losses comparable to injection lubrication when the oil level is low. However, as the oil level increases, so do the power losses due to increased drag within the bearing. This study presents a comprehensive model for calculating drag losses. The proposed drag power loss model accounts for variations in oil level and significantly improves loss predictions. A comparison of existing models with the experimental results shows good agreement for both bearings, demonstrating the effectiveness of the developed model in accounting for oil bath height in loss calculations. Full article

The separation of used engine oil (UEO) with an ultrafiltration (UF) membrane made of commercial copolymer of poly(acrylonitrile-co-methyl acrylate) (P(AN-co-MA)) has been investigated. The P(AN-co-MA) sample was characterized by using FTIR spectroscopy, ¹³C NMR spectroscopy, and XRD. The UF membrane with a mean pore size of 23 nm was fabricated by using of non-solvent-induced phase separation method—the casting solution of 13 wt.% P(AN-co-MA) in dimethylsulfoxide (DMSO) was precipitated in the water bath. Before the experiment, the used engine oil was diluted with toluene, and the resulting UEO solution in toluene (100 g/L) was filtered through the UF membrane in the dead-end filtration mode. Special attention was given to the evaluation of membrane fouling; for instance, the permeability of UEO solution was dropped from its initial value of 2.90 L/(m²·h·bar) and then leveled off at 0.75 L/(m²·h·bar). However, the membrane cleaning (washing with toluene) allowed a recovery of 79% of the initial pure toluene flux (flux recovery ratio), indicating quite attractive membrane resistance toward irreversible fouling with engine oil components. The analysis of the feed, retentate, and permeate by various analytical methods showed that the filtration through the UF membrane made of P(AN-co-MA) provided the removal of major contaminants of used engine oil including polymerization products and metals (rejection—96.3%). Full article

Oil sludge is one of the main pollutants generated by the oil industry. Due to serious pollution and increasing oil production, problems arise every year in the effective treatment of oil sludge. The current study examines the composition and physicochemical characteristics of oil sludge, as well as traditional and new methods for processing oil sludge. With the tightening of environmental protection requirements, oil sludge quality reduction, recycling, and harmless treatment technologies will become necessary in the future. The primary task was to determine the composition of tank oil sludge, separate it from mechanical impurities, and study the influence of ultrasonic treatment and subsequent atmospheric distillation on the extract. The separation of the concentrate and the composition of the tank oil sludge, using an extracted mixture of hexane and benzene, are considered. The use of modern SEM methods, elemental analysis, NMR analysis, IR, ultrasound, and GC–mass spectrometry made it possible to characterize the organic part of reservoir oil sludge and its distillation products. First, 300 g of tank oil sludge was preheated and mixed with 300 mL of solvent (hexane:benzene = 1:1). After mixing with the solvent, the result mixture was filtered. Then, it was placed in an ultrasonic bath and exposed to ultrasound at a frequency of 100 kHz for 30 min. After processing, it was extracted in a Soxhlet apparatus at a temperature of 65 °C to isolate the extract. The resulting extract was analyzed on a gas chromatograph with mass detection. The composition of the extract was as follows (in %): hexane—83.99; total hydrocarbon isomers—7.12; n-hydrocarbons—2.52; benzene—6.37%. At a temperature of 85 °C, the benzene yield was 65.85%. It has been established that the fractions obtained through the distillation of oil sludge at temperatures of 65–85 °C have improved dissolving capacity. It has also been shown that the use of these fractions promotes an increase in the content of hydrocarbon isomers by 12–13% in the extract composition. Full article

Controlling or reducing the adsorption of surfactants on reservoir rock surfaces has been a challenging task in enhanced oil recovery (EOR) methods, as it directly affects the cost-effectiveness of the projects. The adsorption of surfactants on rock surfaces can modify their hydrophobicity, surface charge, and other important parameters that govern EOR processes, such as reducing the interfacial tension between water and oil and increasing permeability. Therefore, understanding the adsorption mechanism on rocks is essential for developing alternatives that improve the effectiveness of these processes. In this work, the adsorption of surfactants on carbonate materials was evaluated considering variations in temperature, contact time, and surfactant concentration. The surfactants used were derived from vegetable oils, aiming for a sustainable approach: saponified coconut oil (SCO), saponified babassu coconut oil (SBCO), and saponified castor oil (SMO). The finite bath method was used, resulting in adsorption efficiencies of 85.74%, 82.52%, and 45.30% for SCO, SBCO, and SMO, respectively. The Sips isotherm and the pseudo-second-order model were found to be suitable for characterizing these systems. The simulation of SCO adsorption isotherms on limestone by the Langmuir model was more accurate than that using the Freundlich model. The limestone showed a negative surface charge of approximately −35.0 mV at pH 6.5; this negative charge varied over a wide pH range. These zeta potential data for the samples confirmed that hydrophobic interactions played an important role in the adsorption of the surfactants. Thermodynamic evaluation indicated spontaneous and endothermic adsorption of SCO on limestone. The systems were also characterized by FTIR, TG/DTG, XRD, XRF, SEM, and zeta potential. Full article

A covalently bonded WO₃/PEDOT hybrid nanorods array has been prepared through solvothermal, oil bath, and electrochemical deposition methods using KH57 as a coupling agent. The obtained WO₃/PEDOT shows substantially increased electrochromic performance with an increased response speed (3.4 s for coloring and 1.2 s for bleaching), excellent optical modulation (86.7% at 633 nm), high coloration efficiency (122.0 cm²/C at 633 nm), and distinguished cyclic stability. It was found that the covalent bond interaction between WO₃ and PEDOT plays an essential role in property enhancement. The covalently bonded inorganic/organic hybrid nanorods array may promise great potential in developing smart-display and energy-efficient materials and devices featuring low energy consumption, cost effectiveness, and environmental protection. Full article

An interconnected sponge structure and porous surface poly (acrylonitrile-co-methyl acrylate) (P(AN-MA)) microfiltration membranes (MF) were fabricated via thermally induced phase separation (TIPS) by using caprolactam (CPL), and acetamide (AC) as the mixed diluent. When the ternary system was composed of 15 wt.% P(AN-MA), 90 wt.% CPL, and 10 wt.% AC and formed in a 25 °C air bath, the membrane exhibited the highest water flux of 8107 L/m²·h. The P(AN-MA) membrane contained hydrophobic groups (-COOCH₃) and hydrophilic groups (-CN), leading it to exhibit oleophobic properties underwater and hydrophobic properties in oil. The membrane demonstrates efficient separation of immiscible oil/water mixtures. The pure water flux of the petroleum ether/water mixture measured 870 L/m²·h, and the pure oil flux of the petroleum tetrachloride/water mixture measured 1230 L/m²·h under the influence of gravity. Additionally, the recovery efficiency of diluents through recrystallization was 85.3%, significantly reducing potential pollution and production costs. Full article

The Cupressaceae family includes species considered to be medicinal. Their essential oil is used for headaches, colds, cough, and bronchitis. Cedar trees like Chamaecyparis lawsoniana (C. lawsoniana) are commonly found in urban areas. We investigated whether C. lawsoniana exerts some of its effects by modifying airway smooth muscle (ASM) contractility. The leaves of C. lawsoniana (363 g) were pulverized mechanically, and extracts were obtained by successive maceration 1:10 (w:w) with methanol/CHCl₃. Guinea pig tracheal rings were contracted with KCl, tetraethylammonium (TEA), histamine (HIS), or carbachol (Cch) in organ baths. In the Cch experiments, tissues were pre-incubated with D-600, an antagonist of L-type voltage-dependent Ca²⁺ channels (L-VDCC) before the addition of C. lawsoniana. Interestingly, at different concentrations, C. lawsoniana diminished the tracheal contractions induced by KCl, TEA, HIS, and Cch. In ASM cells, C. lawsoniana significantly diminished L-type Ca²⁺ currents. ASM cells stimulated with Cch produced a transient Ca²⁺ peak followed by a sustained plateau maintained by L-VDCC and store-operated Ca²⁺ channels (SOCC). C. lawsoniana almost abolished this last response. These results show that C. lawsoniana, and its active metabolite quercetin, relax the ASM by inhibiting the L-VDCC and SOCC; further studies must be performed to obtain the complete set of metabolites of the extract and study at length their pharmacological properties. Full article