Average Droplet Size Research Articles

Simultaneous use of disulphide oil for chemical‐enhanced oil recovery by emulsion formation and stability with asphaltene deposition control

AbstractDisulphide oil (DSO) is a by‐product of oil and gas refining processes that is generated during the removal of mercaptans and the sweetening of light hydrocarbons. Asphalt deposition, especially asphaltene deposition during enhanced oil recovery methods, reduces oil recovery from the reservoir, so the use of a substance such as DSO, which has the ability to control and reduce asphaltene deposition, can be effective in increasing oil recovery from the reservoir. In this research, a micromodel with a fracture design and a matrix that represents fracture reservoirs was utilized. These tests were conducted in two groups. The first group of tests is related to adding DSO to crude oil and using 70 to 30 vol.% oil–water emulsion containing salt, surfactant, and nanoparticles. The second group involved adding DSO to both crude oil and emulsion. The first group aimed at stimulation and the second group aimed at chemical enhanced oil recovery (C‐EOR). The formation and stability of water‐in‐oil emulsion was done by analyzing the average droplet size. As a result, in the first group of tests with the presence of DSO in the oil, by measuring the average diameter before and after injection of AOS surfactant, it was observed that the average droplet size decreased from 6.89 to 4.01 μm, which indicates an increase in the emulsion stability. In the second group, where DSO was present in both oil and water emulsion in injected oil, it can be seen that the average diameter of the droplets in the surfactant decreased from 5.12 to 3.21 μm.

Research on the gravity sedimentation law of watery crude oil in large oil tanks

ABSTRACT Based on field survey data, a numerical simulation method that combines an indoor settling experiment with the Mixture multiphase flow model and the Population Balance Model (PBM) was adopted in this article to study and analyze the sedimentation law of water-containing crude oil in a tank under different initial particle sizes and different continuous-phase viscosities. The results indicate that the maximum error in the comparison of the water content changes at different positions in the sedimentation cylinder after 1 h with experimental values is approximately 8.34%, confirming the precision of the developed settling model. When the initial particle size of liquid droplets in the tank increases from 8 μm to 64 μm, the maximum water content in the tank increases by 1.115%, and the magnitude of the increase in the average droplet size decreases by 90%. As the viscosity of the oil increases (from 35.26 mPa · s to 77.77 mPa · s), the maximum water content in the tank decreases by 1.331%, while the height of the stable water content region increases by 13.2%.

Preparation and characterization of high-methoxyl pectin/glycerides emulsion for pH-responsive, targeting, and sustained release of fat-soluble substances

In this study, a pH-responsive emulsion system was prepared, combining high-methoxyl pectin (HMP) with camellia oil glycerides (CG). The emulsion was characterized as O/W type, with HMP serving as the wall material and CG as the oil phase. The physicochemical properties, pH responsiveness, digestion stability, and encapsulated delivery capabilities of the HMP-CG emulsion were investigated. The emulsion showed an average droplet size of 480.47 ± 76.19 nm, possessing a negative charge and a pronounced core-shell structure. HMP package CG enhanced hydrophilic ability and enabled targeted release within the small intestine through the structural changes of HMP. The presence of HMP and CG increased droplet dispersion and target digestibility of the emulsion system, leading to sustainable small intestine-specific release. Overall, HMP-CG emulsion system, composed of natural materials, exhibited the ability to achieve targeted and controllable release via pH-responsive mechanisms, offering an alternative for developing gel materials incorporating fat-soluble substances.

Aphidicidal activity of nano-emulsions of spearmint oil and carvone against Rhopalosiphum maidis and Sitobion avenae

Different species of aphids, responsible for severe yield losses of cereal crops including wheat, (Triticum aestivum L.) are managed by insecticides, which are harmful to organisms and the environment under field conditions. Therefore, an environment friendly aphidicidal product of plant origin is required. Mentha spicata oil was found to be rich in carvone (81.88%), but the use of its oil and carvone in crop protection is lacking due to their volatility, poor solubility, and stability. A nanoformulaton not only solves these problems but also improve the efficacy and dose of the bioactive compounds. Thus, nano-emulsions of the oil and carvone prepared were characterized, and evaluated against Rhopalosiphum maidis (corn aphid) and Sitobion avenae (wheat aphid) The average droplet size of nano-emulsions of the oil and carvone was found to be 22.1 and 41.21 nm. Nano-emulsion of carvone exhibited higher aphid mortality (LC50 = 0.87–1.94 mg/mL) at 24 h and acetylcholinesterase inhibitory activity (IC50 = 0.07–3.83 mg/mL) compared to the nano-emulsion of the oil (LC50 = 2.87–2.81 mg/mL; IC50 = 1.66–5.34 mg/mL). The repellence index (RI) in nano-emulsion of essential oil was found to be higher (84.73 and 81.72%) at the highest concentration (0.05 µL/cm2) than that of carvone (77.59 and 80.98%) for R. maidis and S. avenae. Further, in silico studies also revealed the favourable binding energy (− 6.6 to − 8.5 kcal/mol) of the main compounds in the oil with acetylcholinesterase, facilitated by hydrophobic interactions and hydrogen bonding. This study suggests that the nano-emulsions of the essential oil and carvone can be explored under field conditions to establish efficacy for their utilization as aphidicidal and repellent products against aphids. In the present study, aphidicial and repellent activities of its essential oil and carvone were reported for the first time against R.maidis and S.avenae.

Development of phyto-compound-based nanoformulation for skin regeneration and its in vitro evaluation

Skin regeneration is a process that regenerates damaged or aged skin cells, resulting in a healthier and younger appearance. The demand for nano dosage forms containing phyto-compounds in the cosmetics industry is increasing daily to control or prevent this process. Phyto-compounds with cell regenerative properties often show limited effectiveness in conventional use due to their low hydrophilicity and molecular weight, as well as their low absorption from the skin. Glycyrrhizic acid (GA), a phyto-compound obtained from licorice root, has many pharmacological properties, including skin regeneration properties. The aim of this study is to develop a highly stable GA-containing nanoemulsion (GA-NE) formulation for topical application, determine its anti-collagenase activity, and evaluate its safety and effectiveness by in vitro cell culture methods. In this context, GA-NEs were synthesized with sixteen production procedures using independent variables (oil, water percentage, surfactant, and homogenization time). The average droplet size, polydispersity index (PdI), and zeta potential (ZP) of the synthesized GA-NEs were determined by dynamic light scattering (DLS) analysis. The heating-cooling cycle (H-C) test result showed that the F4P3 formulation was the most stable formulation. Therefore, 90-day physicochemical stability tests were performed with the F4P3 formulation. In vitro release results revealed that GA was released from NEs at a rate of 93.15 ± 0.61 % within 24 h. An ex vivo permeation and penetration study was performed, and the permeation and penetration profile of F4P3 was determined. In vitro cell culture studies showed that the F4P3 formulation had higher cell viability and regeneration than GA in the HaCaT cell line. Anti-collagenase activity results also revealed a better activity of the F4P3 formulation compared to GA. Consequently, characterization, efficacy, and safety studies showed that the F4P3 formulation could be an innovative cell regeneration product candidate suitable for topical use with high stability.

Alleviation effect of lutein Pickering emulsion formed by casein-dextran conjugates through Maillard reaction against blue light retinal degeneration

With the increasing prevalence of electronic devices, awareness of the risks linked to blue light exposure has significantly heightened. Lutein, a powerful antioxidant, safeguards eye tissue by filtering blue light, while supplementation with docosahexaenoic acid (DHA) enhances retinal function. Adequate intake of these nutrients can help reduce the potential damage from prolonged blue light exposure. The protective effects of lutein and algal oil stabilized with Pickering emulsion were investigated using casein-dextran (CD) conjugates via Maillard reaction. Microstructural analysis revealed a three-dimensional network structure surrounding oil droplets formed by CD conjugates. With the increase of the oil phase ratio from 55 % to 80 %, the average size of Pickering emulsion droplets decreased. Pickering emulsion demonstrated higher viscoelasticity, excellent recovery, thixotropy, and good thermal stability as the oil phase ratio increased. The retention of lutein in CD-75 % Pickering emulsions showed significant improvement under various conditions. Simulated gastrointestinal digestion demonstrated that CD-75 % Pickering emulsions effectively enhanced the lutein bioaccessibility from 19.97 % to 48.99 %. In vivo experiments showed that lutein-loaded Pickering emulsion could effectively relieve blue light-induced retinal degeneration in mice. These findings suggested that Pickering emulsion can serve as a delivery system to protect lutein, offering a nutritional intervention to mitigate blue light-induced retinal degeneration.

Lipase-catalyzed synthesis of erythorbyl oleate and its characterization as a multifunctional emulsifier.

Erythorbyl oleate (EO), a novel emulsifier with multifunctional properties, was synthesized via lipase-catalyzed solvent-free esterification between erythorbic acid and oleic acid. The reaction produced EO of 30.75±1.65mM at 60h, monitored by high-performance liquid chromatography (HPLC) analysis. Purified EO was chemically identified as 6-O-oleoyl-erythorbic acid by HPLC-electrospray ionization/mass spectrometry (ESI-MS), 1H nuclear magnetic resonance (NMR), and 13C NMR analyses, and further investigations on its multifunctionalities were conducted. EO displayed antioxidant activity equivalent to erythorbic acid in 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activities. Investigation of the antibacterial activity of EO against foodborne pathogens showed MICs of 0.27±0.09 and 0.40mM for Bacillus cereus ATCC 10876 and Staphylococcus aureus ATCC 12692, respectively. EO also displayed interfacial properties, lowering interfacial tension between medium-chain triglyceride oil and water to 3.40±0.04 mN/m with a critical micelle concentration of 2.54±0.03mM. Dynamic light scattering analyses of the emulsion stabilized by EO demonstrated a similar polydispersity index (0.15±0.00) to Tween 80-stabilized emulsion (0.28±0.01), with an average droplet size of 173.2±1.8nm. In addition, the EO-stabilized emulsion exhibited a negative surface charge (-56.83±4.30mV) in zeta potential measurements, indicating sufficient electrostatic repulsion between droplets. These results suggest that EO is a multifunctional emulsifier to simultaneously control oxidative rancidification and bacterial spoilage in emulsion-based foods. Practical Application: EO was synthesized via an enzymatic esterification reaction between erythorbic acid and oleic acid. The synthetic process excluded any use of organic solvent, diminishing potential health hazards or environmental pollution associated with chemical reactions. The interfacial properties of the resultant EO, along with excellent antioxidant and antibacterial activities, propose its potential application in emulsion-based foods. Simultaneous control of bacterial spoilage and oxidative rancidification by EO would fulfill the industrial needs for extending shelf life and enhancing consumer safety.

Impact of Fine Water Mist Curtains on Fire Safety in Historic Buildings: A Case Study of Foshan Historical and Cultural District, Guangdong Province, China

ABSTRACT To address inadequate fire separation distances in historical buildings leading to extensive fire spread, practical research employing Fire Dynamics Simulator (FDS) was conducted. The study involved simulating a historical and cultural block in Foshan City to analyze variations in heat flux density and temperatures within a 5-meter radius of windows under fire powers of 1.5 MW, 6 MW, and 10 MW, with window openings at 10%, 25%, and 50%, respectively. The aim was to preserve the original architectural integrity without modifying existing fire separations. Augmentation of fire protection through the implementation of a fine water mist water curtain between buildings was proposed, and its efficacy in smoke and heat insulation was evaluated. Results indicate that, at 1.5 MW fire power, adjacent structures remain relatively secure with current fire separations. However, at 6 MW and 10 MW, fire spread to neighboring buildings was significant regardless of window opening area. Implementation of the water curtain with a nozzle flow coefficient (K) of 80, typical for standard coverage area sprinkler nozzles, and a spacing of 0.8 m, proved effective in enhancing smoke and heat insulation while also offering cost efficiencies. Optimal results were achieved with an average droplet size of 200 µm and nozzle pressure set at 6.0 MPa, corresponding to a nozzle flow rate of 615 L/min. These findings provide valuable insights for drafting specifications for the adaptive reuse of historical buildings and deploying fine water mist water curtains in confined spaces.

Fabrication and characterization of edible Pickering emulsion stabilized by donkey myofibrillar protein

This study aims to investigate the properties of edible Pickering emulsions (PEs) stabilized by donkey myofibrillar protein (DMP). The DMP was characterized by an atomic force microscope and interfacial tensiometer. The PEs stabilized by DMP were characterized by a confocal laser scanning microscope, rheometer, and lumisizer stability analyzer. The results showed that the DMP particles were spherical nanoparticles with an average size of 143.97 nm. The DMP could reduce the oil-water interfacial tension very well. The emulsifying activity index was below 14.06 m2/g, and the emulsion stability index was up to 93.76% when the DMP concentration was above 10 mg/mL. Increasing the concentration of DMP (5 mg/mL to 25 mg/mL) could decrease the emulsion droplet sizes and fluidity of the PEs and increase the viscoelasticity of the PEs. The increase in the oil-water ratio (1:9 to 5:5) resulted in a larger average emulsion droplet size, reduced fluidity, and enhanced viscoelasticity. The increase in DMP concentration (from 5 mg/mL to 25 mg/mL) and oil-water ratio (from 1:9 to 4:6) improved the physical stability of the PEs. These results may expand the application of DMP and provide new insight into developing edible PEs suitable for the formulation of functional foods.

Оценка эффективности завихрения воздуха при распылении водоугольных суспензий пневматической форсункой

Due to modern requirements for environmental protection, introduction of environmentally friendly power engineering technologies involves search and development of new energy sources. One of the ways to meet these requirements and maintain the same level of energy production by thermal power plants is to use multicomponent fuels. The most promising and affordable heavy fuel oil from the point of view of energy, ecology and economy are coal-water slurries (CWS). In this regard, the study of the properties and characteristics of such fuels is relevant. The coal-water slurries have been prepared in a rotary hydrodynamic cavitation generator. A pneumatic atomizer with external mixing is used to spray the coal-water slurries. Interferometric Particle Imaging method is used to determine the average size of fuel droplets after atomization. The authors have conducted experimental studies of the characteristics of atomization of coal-water slurries based on lignite and pyrogenetic liquid with a pneumatic atomizer with a tangential supply of a spraying agent. A three-stage method to prepare lignite-based slurries with pyrogenetic liquid has been tested. It has been established that when using this technique, the fluidity of coal-water fuel is maintained even with the introduction of 20 % by weight of pyrogenetic liquid into the composition of coal-water slurries when replacing both water and coal in equal proportions. The kinematic viscosity of coal-water suspensions increases when pyrogenetic liquid is added, despite a decrease in the concentration of the solid component. The change of suspension density is insignificant. The results of the study of atomization process have shown that the tangential air supply to the atomizer leads to an increase of the jet spraying angle by 6° compared with direct supply. At the same time, the average droplet size in the jet of a two-component CWS with direct air supply is 8 % smaller. The results of the study have made it possible to obtain completely new knowledge that can significantly advance domestic and world science and technology in the field of power engineering, namely the technology of coal-water fuels atomization. Experimental studies have determined the main patterns of influence of the CWS properties and the method of spraying agent supply on the formation of a gas-drop jet. Such patterns will provide conditions for the effective atomization of quite viscous CWS in the combustion chambers of energy boilers. The results obtained will enable designers and constructors to develop highly efficient designs of steam and hot water boilers and gasifiers fueled by CWS.

Time-resolved modeling of dropwise condensation patterns formed on a nanopillared substrate

Instantaneous condensation patterns formed over a vertical nanopillared copper surface are modeled by including drop level details including nucleation, growth, coalescence, droplet jumping and gravitational instability. The vapor phase is taken to be saturated and condensation is driven by a colder wall that imposes a given degree of subcooling. The mathematical model is setup in the form of a condensation cycle, starting from drop nucleation all the way to instability followed by fresh nucleation. In view of the condensing surface being pillared, a variety of droplet morphologies are possible, including Cassie, Wenzel, and partially-wetting that depend on the prevailing condensation conditions. The degree of subcooling is varied over 1 – 28 K, covering a wide range of condensation characteristics from Cassie jumping to Wenzel flooding with increasing temperature difference. Coalescence-based droplet jumping for Cassie and partially-wetting droplet configurations are incorporated as well. Gravitational instability of the largest drop leads to sweeping along the substrate followed by surface renewal and renucleation. With this overall approach, it is possible to explicitly determine the drop-size distribution as a function of time. The entire model is multiscale in space and time, making it a computationally demanding simulation. A domain decomposition framework is used and computations are carried out in a high-performance computing system with a parallel architecture employing message passing interface (MPI). The time-resolved model has been extensively tested against experimental data reported in the literature. The partially-wetting configuration for a subcooling of 8 K has a larger average droplet size and fewer jumping events generating similar heat fluxes as for Cassie droplets at a lower degree of subcooling (ΔT = 5 K) where the average droplet size is smaller and jumping events are frequent. In addition, the Cassie state yields an enhancement factor of around 2.5 relative to a flat surface while Wenzel droplets cause flooding and need subcooling levels as high as 24 K for similar heat flux values.

STUDY ON PREPARATION AND CHARACTERIZATION OF SACHI SEED OIL BASED EMULSION CONTAINING COLLAGEN PEPTIDES

In this study, collagen peptides were carried by a Sacha inchi (sachi) seed oil-based emulsion with Tween 80 under optimal conditions: 26.26% sachi seed oil, 26.06% Tween 80, and 47.68% distilled water. Collagen peptides, varying from 5 - 30% of the total emulsion mass, were dispersed in the aqueous phase before being introduced into the emulsion. Using the sachi seed oil-based emulsion to carry collagen peptides helps prevent the hydrolysis of collagen peptides by acids and enzymes in the digestive system. The characteristics of the emulsion were evaluated using dynamic light scattering, infrared spectroscopy, and ultraviolet-visible spectroscopy. The emulsions loaded with collagen peptides have average droplet sizes ranging from 83.57 - 286.93 nm. Emulsions carrying 5 - 10% collagen peptides exhibit a high stability for up to 30 days. These results demonstrate the potential application of sachi seed oil emulsions carrying collagen peptides in functional foods and healthcare products.

Dielectrophoretic separation of a water-in-oil emulsion

Electric field-assisted separation is considered one of the most effective ways of dehydrating water-in-oil emulsions. In the uniform electric field usually used in electrodehydrators, electrocoalescence leads to droplet enlargement, thus accelerating their gravitational settling. Meanwhile, using a nonuniform field is expected to provide an additional tool for phase spatial separation due to dielectrophoresis while keeping the conditions favorable for electrocoalescence. This study aims to investigate experimentally the dynamics of water-in-oil emulsion in a nonuniform electric field and the efficiency of its separation due to the dielectrophoretic effect. A high-frequency field and emulsions with zero-density contrast were used allowing us to study the action of the dielectrophoretic force in the absence of electrokinetic phenomena and gravitational settling. We found that droplets always move towards the electric field strength gradient, eventually accumulating at the internal electrode. We demonstrate that the separation efficiency increases as the average droplet size, the voltage, the dispersion medium permittivity, and the initial droplet concentration increase. In the latter case the separation enhancement is due primarily to droplet coalescence, the rate of which increases appreciably with increasing concentration. We demonstrate that all the experimental results can be combined into unified dependence based on a simple physical model.

Novel Carboxymethyl Cellulose/Gelatin-Based Film Incorporated with Zein-Stabilized Lemon Essential Oil Pickering Emulsion for the Preservation of Cherries.

In this study, a zein-stabilized lemon essential oil Pickering emulsion (ZLPE) was incorporated into a carboxymethyl cellulose/gelatin (CMC/GL) composite film to develop a bio-based packaging material with bioactive properties. The average droplet size of the ZLPE was measured at 3.62 ± 0.08 μm, with a zeta potential of -31.33 ± 0.32 mV, highlighting its excellent stability. The image results of confocal laser microscopy and scanning electron microscopy validated the uniform distribution of ZLPE in the film. The incorporation of ZLPE reduced the water solubility of films by 45.90% and decreased its water vapor permeability by 22.61%, thereby enhancing its hydrophobicity. Additionally, the ZLPE-loaded film improved mechanical properties, enhanced UV-blocking capabilities, and increased thermal stability. The introduction of ZLPE led to the antioxidant activity of the CMC/GL film increasing by six times the original level and endowed it with outstanding antibacterial properties. As a result, cherries packaged with the ZLPE film demonstrated superior preservation performance and extended shelf life in the preservation experiment, exhibiting the film's potential as a food packaging material.

Evaluating the Stability and Digestibility of Long-Chain Omega-3 Algal Oil Nanoemulsions Prepared with Lecithin and Tween 40 Emulsifiers Using an In Vitro Digestion Model.

The health benefits of long-chain omega-3 polyunsaturated fatty acid (LCn-3PUFA) intake have been well documented. However, currently, the consumption of oily fish (the richest dietary source of LCn-3PUFA) in the UK is far below the recommended level, and the low digestibility of LCn-3PUFA bulk oil-based supplements from triglyceride-based sources significantly impacts their bioavailability. LCn-3PUFA-rich microalgal oil offers a potential alternative for populations who do not consume oily fish, and nanoemulsions have the potential to increase LCn-3PUFA digestibility and bioavailability. The aims of this study were to produce stable algal oil-in-water nanoemulsions with ultrasonic technology to increase DHA digestibility, measured using an in vitro digestion model. A nanoemulsion of LCn-3PUFA algal oil was developed with 6% w/w emulsifiers: lecithin (LE) or an equal ratio of Tween 40 (3%) and lecithin (LTN) (3%), 50% w/w, algal oil and 44% w/w water using rotor-stator and ultrasound homogenization. The in vitro digestion experiments were conducted with a gastric and duodenal digestion model. The results showed the creation of nanoemulsions of LCn-3PUFA algal oils offers potentially significant increases in the bioavailability of DHA in the human body. The increase in digestibility can be attributed to the smaller particle size of the nanoemulsions, which allows for higher absorption in the digestive system. This showed that the creation of nanoemulsions of LCn-3PUFA algal oils offers a potentially significant increase in the bioavailability of DHA in the human body. The LE and LTN nanoemulsions had average droplet sizes of 0.340 ± 0.00 µm and 0.267 ± 0.00 µm, respectively, but the algal oil mix (sample created with same the components as the LTN nanoemulsion, hand mixed, not processed by rotor-stator and ultrasound homogenization) had an average droplet size of 73.6 ± 6.98 µm. The LTN algal oil nanoemulsion was stable in the gastric and duodenal phases without detectable destabilization; however, the LE nanoemulsion showed signs of oil phase separation in the gastric phase. Under the same conditions, the amount of DHA digested from the LTN nanoemulsion was 47.34 ± 3.14 mg/g, compared to 16.53 ± 0.45 mg/g from the algal oil mix, showing DHA digestibility from the LTN nanoemulsion was 2.86 times higher. The findings of this study contribute to the insight of in vitro DHA digestion under different conditions. The stability of the LTN nanoemulsion throughout digestion suggests it could be a promising delivery system for LCn-3PUFAs, such as DHA, in various food and pharmaceutical applications.

Preparation and Properties of Walnut Protein Isolate-Whey Protein Isolate Nanoparticles Stabilizing High Internal Phase Pickering Emulsions.

To enhance the functional properties of walnut protein isolate (WalPI), hydrophilic whey protein isolate (WPI) was selected to formulate WalPI-WPI nanoparticles (nano-WalPI-WPI) via a pH cycling technique. These nano-WalPI-WPI particles were subsequently employed to stabilize high internal phase Pickering emulsions (HIPEs). By adjusting the mass ratio of WalPI to WPI from 9:1 to 1:1, the resultant nano-WalPI-WPI exhibited sizes ranging from 70.98 to 124.57 nm, with a polydispersity index of less than 0.326. When the mass ratio of WalPI to WPI was 7:3, there were significant enhancements in various functional properties: the solubility, denaturation peak temperature, emulsifying activity index, and emulsifying stability index increased by 6.09 times, 0.54 °C, 318.94 m2/g, and 552.95 min, respectively, and the surface hydrophobicity decreased by 59.23%, compared with that of WalPI nanoparticles (nano-WalPI), with the best overall performance. The nano-WalPI-WPI were held together by hydrophobic interactions, hydrogen bonding, and electrostatic forces, which preserved the intact primary structure and improved resistance to structural changes during the neutralization process. The HIPEs stabilized by nano-WalPI-WPI exhibited an average droplet size of less than 30 μm, with droplets uniformly dispersed and maintaining an intact spherical structure, demonstrating superior storage stability. All HIPEs exhibited pseudoplastic behavior with good thixotropic properties. This study provides a theoretical foundation for enhancing the functional properties of hydrophobic proteins and introduces a novel approach for constructing emulsion systems stabilized by composite proteins as emulsifiers.

Optimizing acid microemulsions for cleaner gas production: A study on enhanced adsorption characteristics and implications in retardation

The ultralow interfacial tension between the oil and aqueous phases and the solubilization characteristics in microemulsion systems make them useful for surface cleaning and enhanced oil recovery applications. Microemulsions can form an adsorbed barrier on rock, reducing the acid-rock reaction rate. However, as acid retardation additives, the adsorption patterns of microemulsions are not clearly defined. In this study, microemulsions composed of various electrical surfactants, oil cores, and oil core additives were obtained, and their phase behaviors were investigated. Through adsorption and reaction experiments, cleaning microemulsions that enhance adsorption effects were identified, and their adsorption patterns and adaptability under flow conditions were evaluated. The results demonstrate that incorporating negatively charged polar compounds forms an enhanced adsorption microemulsion characterized by an average droplet size of less than 30 nm after mixing with the acid. The introduction of negatively charged polar compounds resulted in a 177 % increase in adsorption and an 81 % improvement in static retardation effect. Dynamic adsorption tests indicate that the pseudo-second-order model more accurately describes the kinetics of dynamic adsorption of microemulsions on rock surfaces. Under a fixed flow rate, the dynamic retardation rate increased with the concentration of the microemulsion. In practical acidification, the adsorption of microemulsions results mainly from combined electrostatic forces and fluid scouring, characterized by a continuous process of adsorption and desorption. Scanning electron microscope also confirmed that microemulsions can form an adsorptive film on the rock, reducing the acid-rock reaction rate. This study offers practical guidelines for the selection and application of retardation additives, aiming to enhance the ecological compatibility of chemical treatments in low-permeability limestone reservoirs.

Raspberry ketone loaded self nanoemulsifying system of cardamom oil: Assessment of phase behavior, dissolution rate and anti-hyperlipidemic activity

Raspberry ketone (RK), a polyphenolic antioxidant, possesses free radical scavenging against oxidative species and has potential of anti-inflammatory, anti-proliferative and anti-aging activities. Major pharmaceutical restriction associated with RK is its poor dissolution characteristic owing to its hydrophobic nature. Present investigation is an attempt to improve dissolution behavior of RK using cardamom oil (CO) based self nanoemulsifying system (SNE) design and preclinical assessed for anti-hyperlipidemic activity. Demarcation of phase boundaries to exactly locate nanoemulsion areas were explored using ternary plots drawn between CO as oil phase, Tween 80/PEG 600 as Smix at 1:1; 1:2; 2:1 and 3:1 ratios. Previously ternary components were selected on the basis of solubility of RK and aqueous dispersibility of CO. Nanoemulsion areas developed under ternary phase region were quantified using trapezoidal method and found in the order 1:1 > 1:2 > 3:1 > 2:1 of Smix. Aqueous dilutibility of SNEs followed the pattern of dilutions lines drawn across the ternary phase and its interference. Optimized SNE produced 97.1 % transmittance with average droplet size 101 nm, zeta potential −2.27 mV and 0.186 mS/cm conductivity. In-vitro RK release was examined in HCl buffer at pH 1.2 and phosphate buffer at pH 6.8 showed a significant difference in the RK dissolved (p < 0.01) compared to RK suspension (control F6). Optimized formulation (F3) at two doses level (RK loading of 80 and 160 mg/kg) vs. RK suspension (160 mg/kg) was pre-clinically administered for four weeks to assess anti-hyperlipidemic activity. Lipid profile markers (levels of VLDL, HDL, LDL, total triglyceride and total cholesterol) were significantly reduced from nanoemulsion formulation as compared to its suspension. SNE formulations were stable with no appreciable loss in quality and performance for six month storage at 30 ± 2 °C; 65 ± 5 % RH conditions. CO based SNE design significantly extended the ternary area for nanoemulsion development as well as RK solubility; which in turn improved dissolution rate of RK and showed anti-hyperlipidemic activity.

Electrospinning of emulsions stabilized by octenylsuccinylated starch and pullulan

Emulsion electrospinning emerges as a promising technique for producing core-shell nanofibers used in delivering bioactive compounds. This work aims to investigate the feasibility of employing octenylsuccinylated (OS) starch-based emulsions in electrospinning for the fabrication of these nanofibers. The influence of sunflower seed oil concentration, ranging from 5% to 50%, on the emulsions was systematically examined. Increasing the oil concentration affects several key characteristics of the emulsions. These changes include a rise in apparent viscosity (from 0.78 to 7.72 Pa·s at 100 s−1) and average droplet size (from 1.21 to 1.79 μm), as well as a decrease in conductivity (from 727 to 193 μs/cm), leading to a larger average diameter of electrospun fibers, which increased from 294 to 533 nm. Confocal laser scanning microscopy and transmission electron microscopy confirmed the core–shell structure of the fibers. Furthermore, the correlation between fiber size and emulsion properties was discussed, and it was noted that the average fiber diameter, loading capacity, and encapsulation efficiency were significantly affected by emulsion composition and properties. These insights contribute to our understanding of the emulsion electrospinning process and offer a valuable guidance for the development of OS starch-based core–shell electrospun fibers.

Experimental and numerical studies of the processes of spraying coal-water slurries with pneumatic nozzle

The article presents the results of spraying tests of highly viscous coal-water slurries with a pneumatic nozzle and numerical studies of the structure of the gas-drop jet. An increase in the viscosity of coal-water slurries was ensured by introducing a third component into its composition – industrial waste (pyrogenetic liquid). The moderate effect of the slurry viscosity on the average droplet size of coal-water slurries in the jet is due to the high efficiency of the aerodynamic characteristics of the pneumatic nozzle. Introduction of pyrogenetic liquid in the amount of 20 % by weight into the composition of coal-water slurry significantly increases its viscosity. The value of the surface tension of such a slurry is more than doubled. The increase in the average droplet size was no more than 25 % when pyrogenetic liquid content in the composition of coal-water slurry was over 10 % by weight. The average droplet size of coal-water slurries varied in the range from 180 to 210 microns in the study area of gas droplet jet. The results of experimental and numerical studies have shown good convergence. High air velocities at short distances from the nozzle ensure high crushing efficiency of the jet of coal-water slurry. The breakdown of the boundary layer of the liquid from the periphery of the droplets of coal-water slurries and its subsequent destruction was observed at short distances from the nozzle. The values of the Weber number were 100<We<350. At considerable distances from the nozzle (more than 0.5 m), droplets of coal-water slurries were subjected to vibrational crushing (We<50).