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The stability of foam during injection into oil reservoirs is critical, especially under high-temperature and high-salinity conditions. This study formulates foam stabilizers using one polymer, two surfactants, and six types of nanoparticles (NPs). Foam stability was assessed with a static setup, examining factors such as interfacial tension (IFT), bubble characteristics, and solution viscosity through dimensionless numbers: Bond number (Bo), Worthington number (We), and Neumann number (Ne). A new formula for dimensionless electrical conductivity was also introduced. Results showed that at optimal concentrations of the four additives, foam stability improved with NPs due to enhanced surface charge from in situ physiochemical reactions, promoting their migration to the fluid interface. Notably, Ne proved more effective than Bo and We in describing foam stability as it accounts for droplet height's impact on IFT. Acidic NPs demonstrated greater electrostatic force than amphoteric NPs, correlating with improved foam stability reflected in a downward trend in the Ne plot. Additionally, we analyzed the coarsening rate of foam bubbles over time and its relationship to stability. Our findings suggest that dimensionless numbers serve as valuable benchmarks for evaluating foam stability across various additive mechanisms. [ABSTRACT FROM AUTHOR]

Summary: Yellow mustard gum (YMG) and fenugreek gum (FG) are both natural hydrocolloids derived from plant seeds. They showed synergistic effects of increased viscosity upon mixing thus expanding their applications. In this study, a synergistic YMG‐FG (7:3) blend of different total gum concentrations (0%, 0.05%, 0.1%, 0.15%, 0.2% and 0.25%, w/w) was used to develop a whipping cream formula with dairy fat replaced by palm kernel oil. Whipping creams of both liquid emulsion and whipped cream were characterised in terms of particle size, rheological properties, whippability and foam stability, texture and microstructure. The liquid emulsion before whipping showed a shear‐thinning behaviour regardless of the gum concentration. Upon whipping, the overrun of whipped cream decreased while the foam stability increased with increasing gum mixture content. The whipped cream with the addition of gum mixture retained the shape after storing overnight at 22 °C in comparison with two collapsed commercial samples. The whipped cream with 0.1% gum mixture exhibited optimal foam stability and textural properties among all the samples. Overall, the synergistic blend of YMG‐FG can be used as a natural stabiliser in formulating non‐dairy fat whipping cream products to improve foam stability and airy/fluffy texture. [ABSTRACT FROM AUTHOR]

Milk proteins, integral to stable foam production, exhibit seasonal and type-dependent variations. Understanding the impact of protein levels with and without fat on foaming properties is essential for selecting suitable milk types and controlling the foaming process. In this study, we employed steam injection and mechanical mixing to assess foamability, foam stability, and foam structure of (1) reconstituted skim milk powder dispersions (1.5–15% solids concentration, corresponding to 0.5–5.0% protein), (2) reconstituted whole milk powder and commercial whole milk dispersions (0.5% protein), and (3) whole milk with added skim milk powder and milk protein concentrate (3.5 and 4% protein) and butter milk powder (0.5 and 1% total solid content). Results reveal that increasing solids concentration from 1.5 to 15% significantly increased lactose content, viscosity, and surface tension. However, these changes did not impact foamability or foam stability, while slightly decreasing air bubble size. At 0.5% protein, skim milk powder dispersions demonstrated higher foam volume (16 times greater) and more stable foam compared to reconstituted whole milk powder and whole milk dispersions, despite similar foam structure and appearance. These findings emphasize the substantial influence of the protein/fat ratio on milk's foaming properties. Additionally, the addition of skim milk powder, milk protein concentrate, or butter milk powder at the investigated content did not affect the foaming properties of whole milk. [ABSTRACT FROM AUTHOR]

Real-time evaluation of fly ash and air-entrainer (AEA) interaction was performed by acquiring and analyzing videos of the evolving foam layer in cement-fly ash-water mixtures using the foam index test. This modified foam index test or digital foam index, defines two fundamental parameters linked to foam generation and stability, and thus can be used to improve concrete air-entrainment for freeze-thaw durability. The AEA dosage required to produce a metastable foam is defined as foam stability dosage, whereas the incremental AEA dosage beyond the foam stability dosage to achieve a foam layer covering the entire container surface is termed foam efficiency dosage, and the summation of these dosages is the traditional foam index. The foam stability and efficiency dosages are independent parameters as a vinsol resin-based AEA had a higher foam efficiency dosage but a lower foam stability dosage than a sulfonate–based AEA. [ABSTRACT FROM AUTHOR]

High expansion (Hi‐Ex) foam is recommended to suppress the leakage and diffusion of cryogenic liquid due to its light weight and large volume. However, the disadvantages of low stability and high break rate under environmental conditions are all limited the further application in vapor mitigation and fire extinguishing. So that, this paper focus on the effect and mechanism of nanoparticles in stabilizing Hi‐Ex foam. Three kinds of nanoparticles with different concentration were selected to evaluate the effect of foam half‐life and the mechanism of particles on improving the foam stability. The results indicated that different particle concentrations can improve the foam stability to a specific extent, and the maximum improving of half‐life can increase by 95.4% in the presence of the hydrophilic SiO2 at.5 wt%. Meanwhile, the hydrophilicity, size, and morphology of the particles have a specific impact on the foam stability. The foam expansion rate first increased and then decreased. From the microscopic point of view, the bubble size gradually increases with time by two processes of ripening and coalescence and satisfied in a logarithmic distribution. While, the liquid film thickness remarkably decreases due to foam drainage without particles and the adsorption and accumulation of nanoparticles on foam lamella can provide a spatial barrier for the film thinning and the inter bubble diffusion. Finally, the microscopic interaction mechanism on improving the foam stability has been further explored and revealed in these two aspects. [ABSTRACT FROM AUTHOR]

High-temperature steam injection is a primary method for viscosity reduction and recovery in heavy oil reservoirs. However, due to the high mobility of steam, channeling often occurs within the reservoir, leading to reduced thermal efficiency and challenges in enhancing oil production. Foam fluids, with their dual advantages of selective plugging and efficient oil displacement, are widely used in steam-injection heavy oil recovery. Nonetheless, conventional foams tend to destabilize under high-temperature conditions, resulting in poor stability and suboptimal plugging performance, which hampers the efficient development of heavy oil resources. To address these technical challenges, this study introduces a foam system reinforced with Janus nano-graphite, a high-temperature stabilizer characterized by its small particle size and thermal resistance. The foaming agents used in the system are sodium α-olefin sulfonate (AOS), an anionic surfactant, and octadecyl hydroxylpropyl sulfobetaine (OHSB), a zwitterionic surfactant. Under conditions of 250 °C and 5 MPa, the foam system achieved a half-life of 47.8 min, 3.4 times longer than conventional foams. Janus nano-graphite forms a multidimensional network structure in the liquid phase, increasing internal friction and enhancing shear viscosity by 1.2 to 1.8 times that of conventional foams. Furthermore, the foam gel system demonstrated effective steam-channeling control in heterogeneous heavy oil reservoirs, particularly in reservoirs with permeability differentials ranging from 3 to 9. These findings suggest that the Janus nano-graphite reinforced foam system holds significant potential for steam-channeling mitigation in heavy oil reservoirs. [ABSTRACT FROM AUTHOR]

Gliadin nanoparticle (GNP) is a promising foaming agent, but its application is hindered by the limited foam stability under low acidic conditions. Herein, we attempted to tune the foam stability of GNP by coating it with flaxseed gum (FG) and investigated the structure, interfacial behaviors, and foam functionality of gliadin-FG (GFG) particles at pH 4.5. Results showed that the formation of GFG complex particles was driven by an electrostatic interaction between positive charge patches on the surface of GNP (~17 mV) and negative charges in FG molecule (~−13 mV) at all tested ratios. The addition of appropriate amounts of FG (1:0.05) effectively improved the foam stability of GNP. This was because GFG with larger sizes and lower surface charge possessed higher rigidity after coating with FG. When they adsorbed at the air/water interface, their deformation process was slower than that of GNP, as indicated by interfacial dilatational rheology and cryo-SEM, and the covered particles seemed to be more closely distributed to form solid-like and dense interfacial films. Notably, the addition of FG at a higher ratio (1:0.3) promoted the foam stability of GNP by about five folds because the larger GFG with suitable flexibility and wettability could form a stiff interface layer with more significant elastic response, and the unabsorbed particles and FG could form a gel-like network structure in the continuous phase. These characteristics effectively prevented foam disproportionation and coalescence, as well as retard the drainage. Our findings demonstrate that coating GNPs with FG is an effective approach to improve their application in foamed foods. [ABSTRACT FROM AUTHOR]

The replacement of fluorine‐free foam is imminent, but to date, no fluorine‐free foam has reached comparable fire extinguishing performance to AFFF (aqueous film forming foam). The stability of firefighting foam significantly affects its extinguishing performance. In order to better understand the influence of foam formulation physical properties on foam stability, we correlate the foam stability with surface tension and dilational visco‐elasticity based on the AFFF formulation. The results show that, the foam stability rising steadily with the decrease of surface tension, which indicates that low surface tension favors the improvement of foam stability. However, when at the studied highest surface tension, the foam stability elevates slightly instead, demonstrating the surface tension is not the determinant of foam stability. By contrast, the dilational visco‐elasticity shows a closer correlation with foam stability for the consistent tendency. In the case of constantly changing disturbance frequency, the interface dilational elasticity shows a trend of first increasing and then decreasing with the rise of disturbance frequency, whereas the interface dilational viscosity is completely opposite. Different relaxation processes show up for different samples. More attention can be paid to the regulation of dilational visco‐elasticity in the development of fluorine‐free foams, so as to improve their extinguishing ability. [ABSTRACT FROM AUTHOR]

This study examines the impact of CO2 concentration on the stability and plugging performance of polymer-enhanced foam (PEF) under high-temperature and high-pressure conditions representative of the steam front in heavy oil reservoirs. Bulk foam experiments were conducted to analyze the foam performance, interfacial properties, and rheological behavior of CHSB surfactant and Z364 polymer in different CO2 and N2 gas environments. Additionally, core flooding experiments were performed to investigate the plugging performance of PEF in porous media and the factors influencing it. The results indicate that a reduction in CO2 concentration in the foam, due to the lower solubility of N2 in water and the reduced permeability of the liquid film, enhances foam stability and flow resistance in porous media. The addition of polymers was found to significantly improve the stability of the liquid film and the flow viscosity of the foam, particularly under high-temperature conditions, effectively mitigating the foam strength degradation caused by CO2 dissolution. However, at 200 °C, a notable decrease in foam stability and a sharp reduction in the resistance factor were observed. Overall, the study elucidates the effects of gas type, temperature, and polymer concentration on the flow and plugging performance of PEF in porous media, providing reference for fluid mobility control at the steam front in heavy oil recovery. [ABSTRACT FROM AUTHOR]

Chill-haze is a well-known concern for brewers and most commonly involves polyphenols that interact with proline-rich hordein proteins in beers. An effective haze-suppressing effect has previously been established by a proline-specific endoprotease (PEP). In the present study, the protease action of a new Trichoderma reesei expressed PEP enzyme, available as the product BCLEAR™ was studied by assessing its impact on colloidal as well as foam stability and gluten reduction in beer. All malt beers treated with the BCLEAR™ enzyme or beers produced using BCLEAR™ at low dosage levels during fermentation, showed improved colloidal and foam stability when compared to the benchmark PEP investigated. In addition, gluten reduction was investigated using the BCLEAR™ enzyme and was found to have a very good correlation with the observed haze reduction, suggesting that the PEP enzyme dosage can accurately be determined from the calculated gluten content of the given raw materials. Thus, for optimal PEP enzyme use, the brew processes may most efficiently be controlled by following the gluten content, which was demonstrated with use of Lateral Flow Device (LFD) analysis technology. [ABSTRACT FROM AUTHOR]

The ability of foam to reduce CO2 mobility in CO2 sequestration and CO2 enhanced oil recovery processes relies on maintaining foam stability in the reservoir. Foams can destabilize in the presence of oil due to mechanisms impacting individual lamellae. Few attempts have been made to measure the stability of CO2 foams in the presence of oil in a realistic pore network at reservoir pressure. Utilizing lab-on-a-chip technology, the pore-level stability of dense-phase CO2 foam in the presence of a miscible and an immiscible oil was investigated. A secondary objective was to determine the impact of increasing surfactant concentration and nanoparticles on foam stability. In the absence of oil, all surfactant-based foaming solutions generated fine-textured and strong foam that was less stable both when increasing surfactant concentrations and when adding nanoparticles. Ostwald ripening was the primary destabilization mechanism both in the absence of oil and in the presence of immiscible oil. Moreover, foam was less stable in the presence of miscible oil, compared to immiscible oil, where the primary destabilization mechanism was lamellae rupture. Overall, direct pore-scale observations of dense-phase CO2 foam in realistic pore network revealed foam destabilization mechanisms at high-pressure conditions. Highlights: Pore-scale observations of dense-phase CO2 foam in realistic pore network revealed foam destabilization mechanisms at high-pressure conditions. A comprehensive laboratory investigation of CO2 foam stability in the presence of oil at high pressure. [ABSTRACT FROM AUTHOR]

This study aims at exploring properties of fluorine-free foams co-stabilized by nanoparticles (NPs) and surfactant. The mixed dispersion liquids composed of silica NPs, nonionic hydrocarbon surfactant (APG-0810), and organosilicon surfactant (CoatOsil-77) was prepared. The NP-intensified foams under the action of n-heptane (flammable liquid) were focused by analyzing aggregation behavior of surfactants, initial foaming height, foams drainage and decay, and single vertical film stability of the mixed dispersion liquids. The findings show that the presence of surfactants improves surface activity of water obviously. After adding NPs, the interactions between surfactant molecules are destroyed but new aggregates formed. Foaming ability decreases but stability increases significantly with increasing NP concentration. After n-heptane is added, intensified interactions exist among surfactant molecules, NPs, and oil droplet, promoting formation of some larger aggregates and increasing the surface tension and viscosity but decreasing the conductivity and foaming ability. In addition, the presence of n-heptane accelerates foam drainage and volume decay and thinning process of the vertical liquid film. NPs with an appropriate concentration can improve foaming ability, foam stability, and the corresponding oil resistivity of foam. This study can provide theoretical guidance for the development of new fluorine-free foams used for liquid fuel fire. Highlights: Intense interactions exist among SiO2 NPs, surfactant molecules, and oil droplets. Foaming ability is reduced by the presence of SiO2 NPs and oil droplets. SiO2 NPs with concentration above 1% can effectively improve foam oil resistivity. SiO2 NPs enhances foam oil resistivity be improving foam film stability under oil. [ABSTRACT FROM AUTHOR]

The increasing global population and consumer demand for protein pose a serious challenge to the provision of protein-rich diets. Insect farming has been suggested to have a lower environmental impact than conventional animal husbandry which makes insect consumption a more sustainable solution to meet the growing world population's protein requirements. However, there is a reluctancy in the adoption of insect protein especially in the Western diets as whole insect consumption is often met with disgust and resentment. To mitigate against the feeling of disgust and resentment, there have been suggestion to include insects as an ingredient in product development. However, for this to be successfully carried out, the techno-functional properties of insect protein need to be characterised. Therefore, the aim of this study was to isolate and characterise proteins from nine edible insect species. Protein was isolated from nine edible insect species and characterised in terms of the protein content and molecular weight distribution. As crickets are the most common insect food source, the functional characterisation (foaming and emulsification) of protein extracted from house cricket (HC) supernatant protein (SP) was investigated in comparison to commercial whey protein (WP) and pea protein isolate (PPI). The protein content of the buffalo worms and yellow meal worms was significantly (P = 0.000) higher than other insect species such as wild black ants, queen leaf cutter ants, and flying termites. The molecular weight distribution of the nine edible insect species varied from ~ 5 to 250 kDa. HC SP foaming capacity was fourfold and threefold higher than that of WP and PPI respectively. The emulsification potential of HC SP was 1.5 × higher than PPI. The HC protein extract shows promising potential for use in the food industry and represents a potential vehicle for the introduction of insect protein into the diet of societies that are not accustomed to eating insects. [ABSTRACT FROM AUTHOR]

Abstract The stability of foam during injection into oil reservoirs is critical, especially under high-temperature and high-salinity conditions. This study formulates foam stabilizers using one polymer, two surfactants, and six types of nanoparticles (NPs). Foam stability was assessed with a static setup, examining factors such as interfacial tension (IFT), bubble characteristics, and solution viscosity through dimensionless numbers: Bond number (Bo), Worthington number (We), and Neumann number (Ne). A new formula for dimensionless electrical conductivity was also introduced. Results showed that at optimal concentrations of the four additives, foam stability improved with NPs due to enhanced surface charge from in situ physiochemical reactions, promoting their migration to the fluid interface. Notably, Ne proved more effective than Bo and We in describing foam stability as it accounts for droplet height’s impact on IFT. Acidic NPs demonstrated greater electrostatic force than amphoteric NPs, correlating with improved foam stability reflected in a downward trend in the Ne plot. Additionally, we analyzed the coarsening rate of foam bubbles over time and its relationship to stability. Our findings suggest that dimensionless numbers serve as valuable benchmarks for evaluating foam stability across various additive mechanisms.

Improving the stability of CO2 foam is a core concern in CO2 foam flooding oil recovery technology. Using hydrophobic nano‐SiO2 to enhance the stability of CO2 foam is a common approach, but hydrophobic nano‐SiO2 faces challenges, such as easy aggregation, difficult dispersion, and performance needs to improve. In this article, a novel dispersion of styrene‐phenylamine monomer copolymer (PSSN) nanosphere with primary amine groups on the surface was synthesized. The synthesis conditions of PSSN were optimized, and its performance for stabilizing CO2 foam was evaluated. The experimental results demonstrated that PSSN had better performance for stabilizing CO2 foam than that of hydrophobic nano‐SiO2 when using cocamidopropyl betaine (CAB) as the foaming agent. With the CAB concentration of 4000 mg/L and PSSN concentration of 100 mg/L in the brine having salinity of 8460 mg/L, the half‐life of CO2 foam at 90°C was 131 min, which was 43 min longer than that stabilized by hydrophobic nano‐SiO2 under the same conditions. This is for the first time that polystyrene microspheres with amine groups on the surface was used to stabilize CO2 foam. The study provides a new nanoparticle option for stabilizing CO2 foam. [ABSTRACT FROM AUTHOR]

Foamed concrete is increasingly utilized in engineering due to its light weight, excellent thermal insulation, fire resistance, etc. However, its low strength has always been the most crucial factor limiting its large-scale application. This study introduced an innovative method to enhance the strength of foamed concrete by using nano-Al2O3 (NA) as a foam stabilizer. NA was introduced into a foaming agent containing sodium dodecyl sulfate (SDS) and hydroxypropyl methylcellulose (HPMC) to prepare a highly stable foam. This approach significantly improved the foam stability and the strength of foamed concrete. Its drainage volume, settlement distance, microstructure, and stabilizing action were investigated, along with the strength, microstructure, and hydration products of foamed concrete. The presence of NA effectively reduced the drainage volume and settlement distance of the foam. NA is distributed at the gas–liquid interface and within the liquid film to play a hindering role, increasing the thickness of the liquid film, delaying the liquid discharge rate from the liquid film, and hindering bubble aggregation, thereby enhancing foam stability. Additionally, due to the stabilizing effect of NA on the foam, the precast foam forms a fine and uniform pore structure in the hardened foamed concrete. At 28 d, the compressive strength of FC0 (0% NAs in foam) is 2.18 MPa, while that of FC3 (0.18% NAs in foam) is 3.90 MPa, increased by 79%. The reason for this is that NA promotes the formation of AFt, and its secondary hydration leads to the continuous consumption of Ca(OH)2, resulting in a more complete hydration reaction. This study presents a novel method for significantly improving the performance of foamed concrete by incorporating NA. [ABSTRACT FROM AUTHOR]

The use of foam injection as an enhanced oil recovery (EOR) technique has been suggested since the 1960s to address issues with gas injection. Foam is composed of gas, water, and surfactant, which is utilized to stabilize the foam. This study investigates the synergy effect of anionic surfactant and two zwitterionic surfactants on enhancing solution stability. The anionic surfactant used is sodium dodecyl sulfate, while the chosen zwitterionic surfactants are cocamidopropy hydroxy sultine and Cocamido Propyl Betaine. Analyzing the images of the generated foam showed that initially, the small and uniform bubbles are formed in all concentrations. The foam size is then increased and in concentrations higher than a critical value, the bubbles grow faster which is likely due to the formation of micelles and deposition of surfactants. This leads to early collapse of the foam structure. The quantitative half-life results approved that the most optimal compound was obtained with equal proportions of sodium dodecyl sulfate and Cocamido Propyl Betaine with concentration of 3 wt% (1:1 ratio, 0.15 wt%-0.15 wt%). To quantitatively study on foam characteristics, conductivity and interfacial tension tests were performed. The results of the conductivity tests showed that micelles were formed in concentrations of more than 0.3 wt%. Interfacial tension measurements revealed that addition of a small amount of surfactants to the base solution, led to reduction of the interfacial tension value from 29.2 (mN/m) in base solution to less than 1 mN/m for solutions treated with surfactant. [ABSTRACT FROM AUTHOR]

Left‐over frothed milk in most coffeehouses is typically discarded, leading to wastage of a lot of milk due to a common belief that frothed milk is unable to re‐foam. We investigated the foaming and physical properties of frothed reconstituted skim milk (1.5–15%, w/w) foamed up to four times. The results showed that at all investigated solid concentrations and foaming times, milk samples retained their high foamability and foam stability, and uniform micro‐foam structure. Similarly, properties of milk samples including viscosity (1.9–3.3 Pa.s), absolute zeta‐potential (25.5–27.2 mV) and surface tension (54.8–59.7 mN/m) remained unchanged even after re‐foaming multiple times. [ABSTRACT FROM AUTHOR]

Aquafaba is the residual water from cooking chickpea in water. It has a high gelling ability, allowing it to create stable gels. However, those functional properties depend on the legume composition, genotype, cooking time, pressure, and temperature. This study aimed to evaluate the different processes for obtaining aquafaba and compare their nutritional composition and technological characteristics using a systematic review. The authors performed the systematic review by performing specific search strategies for Scopus, Web of Science, Pubmed, Lilacs, Google Scholar, and ProQuest. A total of 17 studies were analyzed. Of them, 17.64% (n = 3) used the wastewater from canned chickpeas, 17.64% (n = 3) compared the wastewater of canned chickpeas and dry grains, and 58.82% (n = 10) used dry chickpeas. Studies used different methods to analyze the protein content. The most used (n = 5) was the Association of Official Analytical Chemists (AOAC). The aquafaba presented carbohydrates at 2.03–2.59 g/100ml; protein at 0.0.8–2.8 g/100ml; and fat at 0.07–0.1 g/100ml. In general, preparing aquafaba followed: soaking (8–10 h at 4 °C—1 chickpea: 4 water), pressure cooking (30 min—2 chickpea: 3 water), and refrigerating (24h/4 °C). In general, the results showed the following steps to prepare aquafaba: soaking for 8–10 h at 4 °C at the proportion of 1:4 (chickpea:water), pressure cooking for 30 min in the proportion of 2:3 (chickpea: water), and refrigerating 24 h/4 °C. These procedures in a homemade aquafaba presented the best results, considering foam development and higher stability. The aquafaba from canned chickpeas has a higher foam-ability and lower emulsion properties than homemade cooking aquafaba. [ABSTRACT FROM AUTHOR]

Foamed concrete, renowned for its lightweight nature and thermal insulating properties, has gained substantial interest in the construction industry. The stability of foamed concrete is directly related to the stability of preformed foam used for making foamed concrete. Foam stability is the prime factor which influences the overall performance and properties of the foamed concrete. Foam stability refers to the ability of the foam to maintain its structure and volume over time. The stability of foamed concrete is greatly impacted by the selection of the foaming agent and the ratio of foaming agent to water (FA/W). Protein based foaming agent (as per ASTM C796/C796M-19) has been used for this study. An excess of water can weaken the foam structure, leading to instability, while inadequate water can lead to issues such as reduced workability and uneven distribution of foam within the mixture. This paper investigates the effect of FA:W ratio on the stability of foam concrete. Three different FA:W ratio i.e. 1:10, 1:20 and 1:30 has been used for this study. Respective slumps to these ratios have also been investigated at different time intervals to check their consistencies. The main aim of this study is to optimize the FA/W ratios on the properties of foamed concrete. Three mix proportions were used to produce foam concrete of 1000kg/m3 density. Impact of aforementioned FA/W ratios on the properties of foamed concrete (As per; IS 2185 part-4) were discussed in this article. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) injection for enhanced oil recovery (EOR) has attracted great attention due to its potential to increase ultimate recovery from mature oil reservoirs. Despite the reported efficiency of CO2 in enhancing oil recovery, the high mobility of CO2 in porous media is one of the major issues faced during CO2 EOR projects. Foam injection is a proven approach to overcome CO2 mobility problems such as early gas breakthrough and low sweep efficiency. In this experimental study, we investigated the foam performance of a commercial anionic surfactant, alpha olefin sulfonate (AOS), in carbonate core samples for gas mobility control and oil recovery. Bulk foam screening tests demonstrated that varying surfactant concentrations above a threshold value had an insignificant effect on foam volume and half-life. Moreover, foam stability and capacity decreased with increasing temperature, while variations in salinity over the tested range had a negligible influence on foam properties. The pressure drop across a brine-saturated core sample increased with an increasing concentration of surfactant in the injected brine during foam flooding experiments. Co-injection of CO2 and AOS solution at an optimum concentration and gas fractional flow enhanced oil recovery by 6–10% of the original oil in place (OOIP). [ABSTRACT FROM AUTHOR]

CO2‐in‐water (C/W) foams have attracted much attention given their eco‐friendliness in recent years. However, limited surfactants were able to effectively adsorb at the supercritical CO2–water (C–W) interface considering the weak solvent strength of CO2, especially at high temperatures. Herein, attempts have been made to design suitable CO2 foaming agents by evaluating the influence of proportions of anionic and cationic surfactants and the affinity between aminopropyl methyl siloxane (APSi) and CO2. Through systematical foamability and foam stability experiments, together with the measurements of C–W equilibrium and dynamic interfacial tensions, the adsorption and stabilization mechanisms of sodium alpha olefin sulfonate (AOS)‐APSi aqueous dispersions on the CO2 foam films are revealed. Excellent foam properties were observed at AOS/APSi mass ratio of 9:1, in which initial foam height (h0) and half‐life period (t1/2) first increased and then decreased with increasing pressure, whereas the interfacial tension decreased with increasing pressure. The results indicate that the interaction of anionic and cationic head‐groups contributes to accelerating the surfactant adsorption rate from bulk to the C–W interface, enhancing foamability and stabilizing foam. Besides, the AOS/APSi mass ratio of 8:2 shows a good affinity for CO2 at 15 MPa, of which h0 is 26% higher and t1/2 is 60% slower than AOS alone. Furthermore, the initial mean bubble area of both 9:1 and 8:2 AOS/APSi mixtures was around half that of AOS alone. This work broadens the design of novel surfactant methodologies including CO2 foam, providing a theoretical guidance for the application of CO2 on enhanced‐oil‐recovery technologies. [ABSTRACT FROM AUTHOR]

Underbalanced foam drilling (UBFD) represents a pivotal technique aimed at enhancing safety and operational efficiency within drilling operations. Despite its recognized benefits, the challenge of maintaining foam stability persists, particularly in conditions characterized by elevated water salinity and alkalinity. This study endeavors to bridge this gap by introducing the eco-friendly Gemini surfactant (GS12) for drilling foams and evaluating its performance under mildly alkaline conditions. Employing a dynamic foam analyzer, diverse foam properties of GS12 foams were systematically assessed, including stability, foamability, and bubble structure. Results elucidate that the optimal surfactant concentration for maximal foam stability stands at 1.5 wt%; however, a threefold concentration increase (from 0.5 to 1.5 wt%) merely yields a 30% improvement, emphasizing the economic viability of a 0.5 wt% concentration for practical UB applications. Additionally, the study demonstrates a correlation between foam stability and water salinity, with seawater exhibiting a twofold reduction in foam half-life compared to deionized water (decreasing from 27 to 13 min), mitigated by the addition of PAC polymer, which increases foam half-life from 13 to 56 min. Moreover, GS12 + PAC foaming systems exhibit surpassing stability compared to a typical commercial blend, boasting a 78% increase in foam half-life (245 min) and a 21% increase in initial foam volume (245 mL), thereby positioning it as a promising candidate for UB drilling applications. The introduction of GS12 for UB drilling and its comprehensive evaluation under mildly alkaline conditions underscore its potential for sustainable foam drilling, advocating for the utilization of environmentally friendly surfactants and green polymers to enhance drilling sustainability and address pressing industry challenges. [ABSTRACT FROM AUTHOR]

Abstract Underbalanced foam drilling (UBFD) represents a pivotal technique aimed at enhancing safety and operational efficiency within drilling operations. Despite its recognized benefits, the challenge of maintaining foam stability persists, particularly in conditions characterized by elevated water salinity and alkalinity. This study endeavors to bridge this gap by introducing the eco-friendly Gemini surfactant (GS12) for drilling foams and evaluating its performance under mildly alkaline conditions. Employing a dynamic foam analyzer, diverse foam properties of GS12 foams were systematically assessed, including stability, foamability, and bubble structure. Results elucidate that the optimal surfactant concentration for maximal foam stability stands at 1.5 wt%; however, a threefold concentration increase (from 0.5 to 1.5 wt%) merely yields a 30% improvement, emphasizing the economic viability of a 0.5 wt% concentration for practical UB applications. Additionally, the study demonstrates a correlation between foam stability and water salinity, with seawater exhibiting a twofold reduction in foam half-life compared to deionized water (decreasing from 27 to 13 min), mitigated by the addition of PAC polymer, which increases foam half-life from 13 to 56 min. Moreover, GS12 + PAC foaming systems exhibit surpassing stability compared to a typical commercial blend, boasting a 78% increase in foam half-life (245 min) and a 21% increase in initial foam volume (245 mL), thereby positioning it as a promising candidate for UB drilling applications. The introduction of GS12 for UB drilling and its comprehensive evaluation under mildly alkaline conditions underscore its potential for sustainable foam drilling, advocating for the utilization of environmentally friendly surfactants and green polymers to enhance drilling sustainability and address pressing industry challenges.

The effects of κ‐casein (κ‐CN) and β‐casein (β‐CN) genetic variant and κ‐CN glycosylation degree (GD, low or high) on interfacial and foaming properties of bovine skim milk were investigated. No significant effect was measured for milks with different ĸ‐CN and β‐CN genetic variants. However, milks of higher GD exhibited lower surface tension, enhanced foamability and differences in secondary protein structure compared to lower GD skim milks. Glycan attachment is believed to affect surface activity and the spread and packing of protein at the foam bubble liquid–air interface, leading to differences in foaming performance. [ABSTRACT FROM AUTHOR]

Background: Although sclerotherapy is widely used to treat vascular malformations (VMs), it is associated with several challenges. One significant issue is the insufficient understanding of the influence of various factors on the stability of polidocanol (POL) foam used in sclerotherapy. Objective: This study aimed to explore the effect of the catheter needle caliber on foam stability when using POL with or without hyaluronic acid (HA) for the treatment of VMs. Methods and materials: The Tessari method generated sclerosant foam using POL both with and without HA. We used catheters and syringe needles of various calibers, and the resulting foam was transferred into new syringes to facilitate a comparison of foam stability. Foam half-life (FHT) was utilized as a metric to assess foam stability. Results: The study found that narrower needle calibers produced a more stable foam when POL was used alone; however, no significant effect was observed when HA was added. Furthermore, when the foam was expelled using catheters and syringe needles of the same size, no noticeable changes in the stability were observed. Conclusion: When choosing needles of varying calibers, their effect on foam stability should be carefully considered, particularly when the foam contains HA. [ABSTRACT FROM AUTHOR]

This study investigated the characteristic and foaming properties of microgels derived from aquafaba, a byproduct generated during chickpea cooking processes. Two distinct approaches were employed for microgel production: a top-down method involving the mechanical disintegration of aquafaba gels through household blending and subsequent high-pressure homogenization and a bottom-up method incorporating an additional shearing step during the gelation of aquafaba. The resulting microgels, when spray-dried, exhibited a raisin-like morphology. Upon rehydration, particle size measurements indicated a prevalence of large microgel particles (D[4,3] values of 16, 10 ± 1, 27 and 13, 70 ± 3, 96 µm for top-down and bottom-up methods, respectively). Fourier transform infrared spectroscopy analysis revealed increased starch crystallinity in microgels produced via the top-down method. At the same time, no significant differences in protein secondary structures were observed between aquafaba powder and microgels. Despite similar particle sizes and structural changes, the impact of the foaming agent type (aquafaba powder vs. microgels) and whipping time on foam properties were demonstrated. Notably, aquafaba microgels resulted in higher foam overrun values (between 709.40 and 962.90%) than those reported in the literature, surpassing traditional protein sources such as egg white and whey protein. However, regarding foam stability, aquafaba powder samples outperformed microgels produced through both top-down and bottom-up methods, regardless of whipping time. The introduction of an ultrasonic bath treatment was found to be necessary to enhance the foam stability of microgel suspensions. To further optimize foaming properties and justify the additional cost associated with microgel production, future research should focus on understanding the adsorption mechanisms of aquafaba microgels at the air–water interface. This investigation will contribute valuable insights into improving foaming characteristics, making aquafaba microgels a promising alternative for various food applications. [ABSTRACT FROM AUTHOR]

Aqueous foams have been used in many underbalanced drilling applications, and their success significantly relies on foam stability. Many studies in the literature have investigated different drilling-foam systems with different surfactants and additives. However, very limited studies reported the foam performance in a high pH environment that is highly recommended for drilling operations to avoid corrosion. Moreover, the stability of the drilling-foam systems should be tested against formation influxes, e.g., brine. However, it is fairly covered in the reported studies. Therefore, this study presents an experimental investigation to evaluate the stability of a set of surfactants (anionic and zwitterionic) at high pH conditions that mimic a typical drilling environment. These surfactants are ammonium alcohol ether sulfate (CPID), coco amido propyl dimethyl betaine, alpha-olefin sulfonates, and coco amido propyl hydroxysultaine. Moreover, the effect of water salinity on the foam stability was investigated. A commercial drilling-foam blend was used as a reference. The tests were conducted using water samples with different salinities, i.e., deionized water, synthetic sea water, and formation water. The analysis of the foam properties such as foam bubble count, structure, foam half-life, and liquid drainage was conducted using a sophisticated foam analyzer. The surfactants used for foaming exhibited have varying impact on foaming properties, i.e., foam stability, structure, and foamability, with increasing water salinity. Therefore, it is recommended to investigate them independently to evaluate their compatibility with different water salinities. The results showed that the surfactant: Ammonium alcohol ether sulfate (CPID) is suggested to be a good potential candidate for UB drilling applications. This is because it showed good compatibility with different water salinities with no considerable impact on its formability. Moreover, it showed promising stability which increases with increasing water salinity, unlike the other tested surfactants. The analysis also showed that CPID surfactant had very comparable foam characteristics to the commercial blend and hence promotes its potentiality to be a good drilling foam. This study would help provide a better understanding of the drilling foam in a mildly alkaline environment. Besides, it is substantial to improve operational safety and cost control, as well as mitigate the risks associated with the application of foam drilling. [ABSTRACT FROM AUTHOR]

Foam stability was one of the important factors affecting the flotation process. In order to investigate the influence of quartz on the stability of flotation foam, the foam stability and froth drainage test were carried out to study the foam stability of quartz under different concentration of collector, particle size and mass concentration. The influence mechanism of quartz on the stability of flotation foam was further analyzed by contact angle measurement, Zeta potential test, foam optical image observation, surface tension and slurry viscosity measurements. The results showed that with the increase of dodecylamine concentration, the foaming ability of the solution increased, and the foam stability increased first and then decreased. This was mainly because dodecylamine significantly reduced the surface tension of the solution system and slowed down the average flow rate of liquid foam film draining in Plateau channel. The hydrophobicity of quartz surface gradually increased and the foam stability was enhanced. However, when the concentration of dodecylamine was greater than 60 mg/L and the three-phase contact angle of quartz exceeded 90°, the strongly hydrophobic particles no longer had the effect of stabilizing bubbles, but followed the mechanism of bridging and anti-wetting, and the foam stability decreased. The finer the quartz particle size was, the greater the mass concentration was, which increased the slurry viscosity, hindered the liquid film drainage and enhanced the foam stability. The froth drainage test results showed that the larger the quartz particle size was, the faster the bubble burst rate was, which was in line with the foam stability test results. The electrostatic action of dodecylamine adsorbed on quartz surface changed the electronegativity of quartz surface. Under the condition of flotation test, it was beneficial to form stable foam system. The foam image showed that quartz adhered to the surface of the bubble film, increasing the thickness of the liquid film and forming a tightly arranged shell structure in the boundary region of the two bubbles and Plateau Border, enhancing the stability of the foam. [ABSTRACT FROM AUTHOR]

Foam has been successfully used to improve mobility control in the process of enhanced oil recovery, yet the instability of foam limits its application. Modified nanoparticles with varying wettability were prepared by reacting 3- methacryloxypropyltrimethoxysilane (KH570) with spherical SiO2 nanoparticles in this study. Fourier transform infrared (FTIR) spectra and the measured contact angles were used to characterize the surface properties of the modified SiO2 particles, and the foam stabilization effects of wettability SiO2 were compared. Pore-scale visualization experiments were conducted using a 2D micromodel to identify the prevailing enhanced oil recovery (EOR) mechanisms of modified nano SiO2-Sodium alpha-olefin Sulfonate (AOS) foam flooding. The results indicate that modified SiO2 effectively improves foam stability by adsorbing on the bubble surface and forming a mesh-like structure. The optimum contact angle of the particles is approximately 60°, resulting in a significant increase in drainage half- life by 29.4% compared to foam stabilized only by AOS. Additionally, Foam stabilized by modified SiO2 demonstrates superior dynamic stability and deformation resistance. The modified SiO2 stabilized foam exhibits enhanced interfacial viscoelasticity and plugging and profile control performance, surpassing AOS foam in displacing more residual oil in dead-end pores. The oil recovery of the micro model was determined by ImageJ software. KH570@ SiO2 (0.2wt%)-AOS (0.2wt%) foam flooding increased the recovery by 8.7% compared to AOS (0.2wt%) foam flooding. [ABSTRACT FROM AUTHOR]

Summary: Aerated emulsions formulated with vegetable oils have been widely consumed with health demands of tea‐based drinks and coffee. In comparison with its traditional counterparts consisting of 30%–40% of fats, that is, whipping creams, the aerated emulsions containing less than 20% vegetable oils are classified as low fat‐cream‐like products and popular with consumers preferring fat‐reduced foods. However, unstable whipping capabilities are the typical quality defects of these low fat‐emulsions, which is highly related with partial coalescence of fat globules. In the present study, effects of unsaturation degree and fatty acid species of fat matrix on whipping capabilities of the aerated emulsions were evaluated by analysing crystal networks, partial coalescence behaviours, whipping performance, and foam structure and stabilities. Increase of fat unsaturation from 10% to 30% improved fat crystal structure and partial coalescence significantly. In particular, 10%–15% of medium chain‐fatty acids present in the emulsions with 30% unsaturated fats tended to crystallise into well‐packed thicker crystals, and to exhibit the highest partial coalescence rate with nearly 60% of solid fat content at whipping temperature. Both the fat species and unsaturation contributed to forming smooth appearance and desirable foam networks after whipping. In contrast, further increase in unsaturation resulted in significant reduction of adsorbed proteins, contributing to excessive aggregation of fat globules. Therefore, it presented negative effects on partial coalescence as well as foam firmness and stabilities. The results figured out characteristics of fat matrix for the manufacture of low fat‐aerated creams with improved whipping capabilities. [ABSTRACT FROM AUTHOR]

Nanoparticles can be adsorbed at the gas-liquid interface to improve the stability of foam. However, homogeneous nanoparticles exhibit low surface activity, and their migration to the gas-liquid interface requires significant energy input. This leads to harsh foaming conditions and severely limits the application of homogeneous nanoparticles in foam stability. A microfluidic visualisation model for the study of Janus nanoparticle complex systems was used to investigate the formation behaviour of trapped bubbles in a single connected pore-throat model. The foam generated in the pore showed reduced quantities, sizes, improved quality, and enhanced stability compared to both surfactant systems and hydrophilic nanoparticle complex systems. [ABSTRACT FROM AUTHOR]

Copyright of China Journal of Oral & Maxillofacial Surgery is the property of Shanghai Jiao Tong University, College of Stomatology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Nonferrous Metals (Mineral Processing Section) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For years, cold plasma processing has been used as a non-thermal technology in industries such as food. As interfacial properties of protein play a remarkable role in many processes, this study investigates the effect of cold plasma on the foaming and interfacial behavior of WPI. The objective of this study is to evaluate the effect of different gases (air, 1:1 argon–air mixture, and sulfur hexafluoride (SF6)) used in low-pressure cold plasma (VCP) treatments of whey protein isolate (WPI) on the surface and foaming behavior of aqueous WPI solutions. Dynamic surface dilational elasticity, surface tension isotherms, surface layer thickness, and the foamability and foam stability were investigated in this study. VCP treatment did not significantly affect the adsorption layer thickness. However, an increase in induction time, surface pressure equilibrium value, and aggregated size is observed after SF6VCP treatment, which can be attributed to the reaction of WPI with the reactive SF6 species of the cold plasma. The surface dilational elastic modulus increased after VCP treatment, which can be related to the increased mechanical strength of the protein layer via sulfonation and aggregate formation. VCP treatment of WPI increases the foam stability, while the average diameter of foam bubbles and liquid drainage in the foam depends on the gas used for the cold plasma. [ABSTRACT FROM AUTHOR]

The interaction between nanoparticles and cationic surfactants is an exciting and emerging field in interfacial science. This area of research holds significant promise, linking fundamental principles to practical applications in a variety of industries, including chemical processes, biomedical applications and the petroleum industry. This study explores the interaction between dodecyltrimethylammonium bromide (DoTAB) and silica (SiO2) nanoparticles, investigating their influence on dynamic interfacial properties and foam characteristics. Through equilibrium and dynamic surface tension measurements, along with examining the dilational visco-elasticity behavior, this research reveals the complex surface behavior of DoTAB/SiO2 mixtures compared to individual surfactant solutions. The foamability and stability experiments indicate that the addition of SiO2 significantly improves the foam stability. Notably, stable foams are achieved at low SiO2 concentrations, suggesting a cost-effective approach to enhancing the foam stability. This study identifies the optimal stability conditions for 12 mM DoTAB solutions, emphasizing the crucial role of the critical aggregation concentration region. These findings offer valuable insights for designing surfactant-nanoparticle formulations to enhance foam performance in various industrial applications. [ABSTRACT FROM AUTHOR]

Foam stability tests were performed using sodium dodecyl sulfate (SDS) surfactant and SiO2 nanoparticles as foaming system at different asphaltene concentrations, and the half-life of CO2 foam was measured. The mechanism of foam stability reduction in the presence of asphaltene was analyzed by scanning electron microscope (SEM), UV adsorption spectrophotometric concentration measurement and Zeta potential measurement. When the mass ratio of synthetic oil to foam-formation suspension was 1:9 and the asphaltene mass fraction increased from 0 to 15%, the half-life of SDS-stabilized foams decreased from 751 s to 239 s, and the half-life of SDS/silica-stabilized foams decreased from 912 s to 298 s. When the mass ratio of synthetic oil to foam-formation suspension was 2:8 and the asphaltene mass fraction increased from 0 to 15%, the half-life of SDS-stabilized foams decreased from 526 s to 171 s, and the half-life of SDS/silica-stabilized foams decreased from 660 s to 205 s. In addition, due to asphaltene-SDS/silica interaction in the aqueous phase, the absolute value of Zeta potential decreases, and the surface charges of particles reduce, leading to the reduction of repulsive forces between two interfaces of thin liquid film, which in turn, damages the foam stability.

High-temperature steam injection is a primary method for viscosity reduction and recovery in heavy oil reservoirs. However, due to the high mobility of steam, channeling often occurs within the reservoir, leading to reduced thermal efficiency and challenges in enhancing oil production. Foam fluids, with their dual advantages of selective plugging and efficient oil displacement, are widely used in steam-injection heavy oil recovery. Nonetheless, conventional foams tend to destabilize under high-temperature conditions, resulting in poor stability and suboptimal plugging performance, which hampers the efficient development of heavy oil resources. To address these technical challenges, this study introduces a foam system reinforced with Janus nano-graphite, a high-temperature stabilizer characterized by its small particle size and thermal resistance. The foaming agents used in the system are sodium α-olefin sulfonate (AOS), an anionic surfactant, and octadecyl hydroxylpropyl sulfobetaine (OHSB), a zwitterionic surfactant. Under conditions of 250 °C and 5 MPa, the foam system achieved a half-life of 47.8 min, 3.4 times longer than conventional foams. Janus nano-graphite forms a multidimensional network structure in the liquid phase, increasing internal friction and enhancing shear viscosity by 1.2 to 1.8 times that of conventional foams. Furthermore, the foam gel system demonstrated effective steam-channeling control in heterogeneous heavy oil reservoirs, particularly in reservoirs with permeability differentials ranging from 3 to 9. These findings suggest that the Janus nano-graphite reinforced foam system holds significant potential for steam-channeling mitigation in heavy oil reservoirs.

Copyright of Oilfield Chemistry is the property of Sichuan University, Oilfield Chemistry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The volume and stability of wine foams are influenced by many components of the matrix, especially proteins. However, the synergistic or inhibiting effects among these protein fractions, as well as their interactions with other wine components, are still under study. The present research aims to understand the individual and cooperative effects of different wine proteins and glycoproteins on the volume and stability of foams. To address this objective, different protein fractions were purified from a Chardonnay white wine and tested in different model wine conditions (with/without ethanol), along with a commercial yeast-based oenological additive. Different fractions were considered, including total protein fraction (FT), Mannoproteins (MP), and non-mannosylated proteins (NMP), as well as a protein fraction soluble in ammonium sulfate (FSA). These protein fractions were characterized, and their foaming properties were evaluated using a modified Rudin apparatus. The results showed that FT exhibited higher foam expansion (FE%) compared to its subfractions (NMP and MP) that, when tested individually, did not guarantee optimal foam formation. This suggests that foaming properties are enhanced when both glycosylated and non-glycosylated proteins are present in the system. Additionally, the foaming behavior was influenced by the presence of ethanol in the model wine. The FSA fraction demonstrated high foam expansion and stability, with ethanol enhancing foam expansion but reducing stability. A commercial yeast-based oenological additive, mainly containing glycoproteins, was also tested and behaved similarly to MP. This study provides valuable insights for sparkling wine producers to optimize practices for enhancing product quality and confirm previous research regarding the role of the synergy between MP and NMP in wine foam formation and stability. [ABSTRACT FROM AUTHOR]

The aim of this study was to make eggs microbially safe and increase their durability without damaging the functional properties of the albumen and preserving the solubility of its proteins as much as possible by the solution plasma technique. The pH, Brix, density, and viscosity values of samples decreased during treatment (p <.05 except pH). Although the L* and a* values of both the albumen and egg foam decreased, the b*, hue angle, and chroma values of both increased during treatment. The L* and a* values of the albumen decreased by 7.01 and 1.89 units, and the values of the egg foam decreased by 10.93 and 1.03 units, respectively. At the end of the treatment, foaming capacity and foam stability were decreased by 25% and 21.42%, respectively. Foaming capacity values obtained as a result of this treatment were higher and foam stability values were lower compared to the values obtained in pasteurization of eggs by heat treatment. The count of the two pathogenic bacteria inoculated into the albumen decreased during the treatment (p <.05), the count of Salmonella Enteritidis decreased to 0, and the count of Staphylococcus aureus decreased by 1.09 log cfu/g at the end of the treatment. Compared to current heat treatments, solution plasma treatment caused significantly less adverse effects on albumen quality characteristics. In particular, the foaming properties of the albumen were much less affected by this method and remained at higher values compared to the values achieved by other methods. The treatment also produced a microbiologically safer product. [ABSTRACT FROM AUTHOR]

Foam stability tests were performed using sodium dodecyl sulfate (SDS) surfactant and SiO2 nanoparticles as foaming system at different asphaltene concentrations, and the half-life of CO2 foam was measured. The mechanism of foam stability reduction in the presence of asphaltene was analyzed by scanning electron microscope (SEM), UV adsorption spectrophotometric concentration measurement and Zeta potential measurement. When the mass ratio of synthetic oil to foam-formation suspension was 1:9 and the asphaltene mass fraction increased from 0 to 15%, the half-life of SDS-stabilized foams decreased from 751 s to 239 s, and the half-life of SDS/silica-stabilized foams decreased from 912 s to 298 s. When the mass ratio of synthetic oil to foam-formation suspension was 2:8 and the asphaltene mass fraction increased from 0 to 15%, the half-life of SDS-stabilized foams decreased from 526 s to 171 s, and the half-life of SDS/silica-stabilized foams decreased from 660 s to 205 s. In addition, due to asphaltene-SDS/silica interaction in the aqueous phase, the absolute value of Zeta potential decreases, and the surface charges of particles reduce, leading to the reduction of repulsive forces between two interfaces of thin liquid film, which in turn, damages the foam stability. [ABSTRACT FROM AUTHOR]

BackgroundAlthough sclerotherapy is widely used to treat vascular malformations (VMs), it is associated with several challenges. One significant issue is the insufficient understanding of the influence of various factors on the stability of polidocanol (POL) foam used in sclerotherapy.ObjectiveThis study aimed to explore the effect of the catheter needle caliber on foam stability when using POL with or without hyaluronic acid (HA) for the treatment of VMs.Methods and materialsThe Tessari method generated sclerosant foam using POL both with and without HA. We used catheters and syringe needles of various calibers, and the resulting foam was transferred into new syringes to facilitate a comparison of foam stability. Foam half-life (FHT) was utilized as a metric to assess foam stability.ResultsThe study found that narrower needle calibers produced a more stable foam when POL was used alone; however, no significant effect was observed when HA was added. Furthermore, when the foam was expelled using catheters and syringe needles of the same size, no noticeable changes in the stability were observed.ConclusionWhen choosing needles of varying calibers, their effect on foam stability should be carefully considered, particularly when the foam contains HA.

Foam has been successfully used to improve mobility control in the process of enhanced oil recovery, yet the instability of foam limits its application. Modified nanoparticles with varying wettability were prepared by reacting 3-methacryloxypropyltrimethoxysilane (KH570) with spherical SiO2 nanoparticles in this study. Fourier transform infrared (FTIR) spectra and the measured contact angles were used to characterize the surface properties of the modified SiO2 particles, and the foam stabilization effects of wettability SiO2 were compared. Pore-scale visualization experiments were conducted using a 2D micromodel to identify the prevailing enhanced oil recovery (EOR) mechanisms of modified nano SiO2-Sodium alpha-olefin Sulfonate (AOS) foam flooding. The results indicate that modified SiO2 effectively improves foam stability by adsorbing on the bubble surface and forming a mesh-like structure. The optimum contact angle of the particles is approximately 60°, resulting in a significant increase in drainage half-life by 29.4% compared to foam stabilized only by AOS. Additionally, Foam stabilized by modified SiO2 demonstrates superior dynamic stability and deformation resistance. The modified SiO2 stabilized foam exhibits enhanced interfacial viscoelasticity and plugging and profile control performance, surpassing AOS foam in displacing more residual oil in dead-end pores. The oil recovery of the micro model was determined by ImageJ software. KH570@SiO2 (0.2wt%)-AOS (0.2wt%) foam flooding increased the recovery by 8.7% compared to AOS (0.2wt%) foam flooding.

Foamed concrete is increasingly utilized in engineering due to its light weight, excellent thermal insulation, fire resistance, etc. However, its low strength has always been the most crucial factor limiting its large-scale application. This study introduced an innovative method to enhance the strength of foamed concrete by using nano-Al2O3 (NA) as a foam stabilizer. NA was introduced into a foaming agent containing sodium dodecyl sulfate (SDS) and hydroxypropyl methylcellulose (HPMC) to prepare a highly stable foam. This approach significantly improved the foam stability and the strength of foamed concrete. Its drainage volume, settlement distance, microstructure, and stabilizing action were investigated, along with the strength, microstructure, and hydration products of foamed concrete. The presence of NA effectively reduced the drainage volume and settlement distance of the foam. NA is distributed at the gas–liquid interface and within the liquid film to play a hindering role, increasing the thickness of the liquid film, delaying the liquid discharge rate from the liquid film, and hindering bubble aggregation, thereby enhancing foam stability. Additionally, due to the stabilizing effect of NA on the foam, the precast foam forms a fine and uniform pore structure in the hardened foamed concrete. At 28 d, the compressive strength of FC0 (0% NAs in foam) is 2.18 MPa, while that of FC3 (0.18% NAs in foam) is 3.90 MPa, increased by 79%. The reason for this is that NA promotes the formation of AFt, and its secondary hydration leads to the continuous consumption of Ca(OH)2, resulting in a more complete hydration reaction. This study presents a novel method for significantly improving the performance of foamed concrete by incorporating NA.

Carbon dioxide (CO2) injection for enhanced oil recovery (EOR) has attracted great attention due to its potential to increase ultimate recovery from mature oil reservoirs. Despite the reported efficiency of CO2 in enhancing oil recovery, the high mobility of CO2 in porous media is one of the major issues faced during CO2 EOR projects. Foam injection is a proven approach to overcome CO2 mobility problems such as early gas breakthrough and low sweep efficiency. In this experimental study, we investigated the foam performance of a commercial anionic surfactant, alpha olefin sulfonate (AOS), in carbonate core samples for gas mobility control and oil recovery. Bulk foam screening tests demonstrated that varying surfactant concentrations above a threshold value had an insignificant effect on foam volume and half-life. Moreover, foam stability and capacity decreased with increasing temperature, while variations in salinity over the tested range had a negligible influence on foam properties. The pressure drop across a brine-saturated core sample increased with an increasing concentration of surfactant in the injected brine during foam flooding experiments. Co-injection of CO2 and AOS solution at an optimum concentration and gas fractional flow enhanced oil recovery by 6–10% of the original oil in place (OOIP).