Novel foaming agent used in preparation process of aluminum foams

The performances of a novel foaming agent used in the preparation process of aluminum foams were investigated, and the effects of some factors, such as addition of the foaming agent, foaming temperature on the porosity, and appearance of aluminum foams were also discussed. Experimental results show that the novel foaming agent has a wide decomposition temperature range and a mild decomposed rate; the foaming agent has the ability to enhance the viscosity of aluminum melt, as a result, an extra viscosifier such as Ca or SiCp is unnecessary while using this foaming agent; the bubble-free zone in material decreases and the foaming effi- ciency increases with the increase of foaming agent; the bubble-free zone disappears and the foaming efficiency is near 100% when the addition of foaming agent is more than 1.4wt%; the porosity of the aluminum foam increases with the increase of foaming agent when the addition of foaming agent is less than 2.2wt%.

Experimental assessments of methanol-based foaming agent in latex modified foamed binders and warm asphalt mixtures

Latex is one of the natural rubbers that is used to enhance the performance of asphalt pavement for the last few decades.The presence of latex,which is categorized as an elastomer,helps to improve pavement performance and durability.Conversely,higher viscosity of latex modified asphalt binder increases the production-temperatures of asphalt mixture,thus consuming higher energy during asphalt mixture’s production stage.In this study,the effectiveness of methanol as an energy-efficient foaming agent was assessed to reduce the viscosity and enhance the workability of the modified asphalt binder.The basic and rheological properties of the asphalt binders were determined through multiple laboratory tests including expansion ratio and half-life,rotational viscosity,softening point,torsional recovery,and dynamic shear rheometer.The properties of asphalt mixtures were assessed through the service characteristics,mechanical performance,and moisture resistance criteria.It was found that the presence of latex results in an approximately twofold higher expansion ratio and a lower half-life of the asphalt binder at about the same ratio.Through the rotational viscosity test,the application of methanol into asphalt binder decreased the viscosity and led to better workability,despite the addition of latex as an asphalt modifier.The application of methanol into asphalt binder improved the workability of mixture samples and lowered the compaction energy of the compaction process,which are the crucial criteria for a better mixing and compaction process.Methanol foamed asphalt mixtures with latex show much higher resistance to moisture damage and stiffness than control sample even though they were prepared at a lower temperature.

Enhanced oil recovery by nonionic surfactants considering micellization, surface, and foaming properties

Surfactants for enhanced oil recovery are important to study due to their special characteristics like foam generation,lowering interfacial tension between oleic and aqueous phases,and wettability alteration of reservoir rock surfaces.Foam is a good mobility control agent in enhanced oil recovery for improving the mobility ratio.In the present work,the foaming behavior of three nonionic ethoxylated surfactants,namely Tergitol 15-S-7,Tergitol 15-S-9,and Tergitol 15-S-12,was studied experimentally.Among the surfactants,Tergitol 15-S-12 shows the highest foamability.The effect of Na Cl concentration and synthetic seawater on foaming behavior of the surfactants was investigated by the test-tube shaking method.The critical micelle concentrations of aqueous solutions of the different nonionic surfactants were measured at 300 K.It was found that the critical micelle concentrations of all surfactants also increased with increasing ethylene oxide number.Dynamic light scattering experiments were performed to investigate the micelle sizes of the surfactants at their respective critical micelle concentrations.Core flooding experiments were carried out in sand packs using the surfactant solutions.It was found tha t22% additional oil was recovered in the case of all the surfactants over secondary water flooding.Tergitol 15-S-12exhibited the maximum additional oil recovery which is more than 26%after water injection.

THE STRUCTURE CONTROL OF ALUMINUM FOAMS PRODUCED BY POWDER COMPACTED FOAMING PROCESS

A new technique, powder compact foaming process for the production of aluminumfoams has been studied in this article. According to this method, the aluminum pow-der is mixed with a powder foaming agent (TiH_2). Subsequent to mixing, the powderblend is hot compacted to obtain a dense semi--finished product. Upon heating to tem-peratures within the range of the melting point, the foaming agent decomposes to evolvegas and the semi--finished product expands into a porous cellular aluminum. Foamingprocess is the key in this method. Based on experiments, the foaming characteris-tics were mainly analyzed and discussed. Experiments show that the aluminum--foamwith closed pores and a uniform cell structure of high porosity can be obtained usingthis method by adjusting the foaming parameters: the content of foaming agent andfoaming temperature.

Investigation on the foaming behaviors of NC-based gun propellants

To prepare the porous NC-based(nitrocellulose-based) gun propellants,the batch foaming process of using supercritical CO_2 as the physical blowing agent is used.The solubilities of CO_2 in the single-base propellants and TEGDN(trimethyleneglycol dinitrate) propellants are measured by the gravimetric method,and SEM(scanning electron microscope) is used to observe the morphology of foamed propellants.The result shows that a large amount of CO_2 could be dissolved in NC-based propellants.The experimental results also reveal that the energetic plasticizer TEGDN exerts an important influence on the pore structure.The triaxial tensile failure mechanism for solid-state nucleation is used to explain the nucleation of NC-based propellants in the sol id state.Since some specific foaming behaviors of NC-based propellants can not be explained by the failure mechanism,a solid-state nucleation mechanism which revises the triaxial tensile failure mechanism is proposed and discussed.

Preparation of Ceramic Foams Suitable for Aircraft Arresting by the Airport Runway Based on a Protein Foaming Agent

Crushable ceramic foams are more suitable to be used as an arrestor material applied in engineered materials arresting system （EMAS） for airport runway for their properties of widely controllable strength, negligible crushing-rebounding behavior, durability, and chemically-inert composition, comparing with traditional concrete foams. The synthesis of ceramic foams adopted direct-foaming method and used an animal protein as foaming agent. Kaolin, talc powder and alumina were the main raw materials. Effects of the ratios of raw materials, calcination temperatures, heating rates, holding time, viscosities of potyvinyl alcohol （PVA） solution as well as the amounts of protein foaming agent and water on microscopic structure, densities, compressive strength and open porosities of ceramic foams were investigated systematically. The results indicate that ceramic foams with typical pore sizes 100-300 μm, open porosities from 73.1% to 91.5%, densities from 0.25 to 0.62 g.cm-3, compressive strength from 0.19 to 4.89 MPa, are obtained by properly adjusting the parameters mentioned above. And the mechanical strength meets the requirement for the EMAS for airport runway. In addition, good correlations are observed among compressive strength, open porosity, microscopic structure, and crystal phase. Furthermore, the possibility of producing the general dimensions of such aircraft arresting components with the proposed method was also discussed.

Study on Foaming Behaviour of Molten Slag during Smelting Reduction with Iron Bath

The molten slag in smelting reduction with iron bath has peculiar behaviour for its high FeO concentration. Slag foaming is effected by the concentration and reduction rate of FeO, basicity of slag and temperature. Addition of granulated coke can greatly decrease slag foaming extent in the process of smelting reduction with iron bath. The anti-foaming capacity of granulated coke is the best when the ratio of coke used for coke layer to total coke used in smelting reduction is controlled at about 20%.

Fabrication and characterization of novel foaming polyurethane hollow fiber membrane

Foam-like materials had attracted great interest as promising absorbent. In this study, thermoplastic polyurethane(TPU) block sponge was synthesized. Polyester(PET) braid tubular reinforced polyurethane(PU) spongy hollow fiber membrane was prepared by a concentric circular spinning method. The method was woven from an outer coated water-blown PU separation layer and inner PET braid tubular. We have developed a simple and useful preparation technique for the PU spongy hollow fiber membrane. For the first time, the PU spongy hollow fiber membrane was prepared using a coating and controlled foaming technique. The influence of toluene isocyanate index on the physical properties, morphology, and structure of flexible PU sponge was discussed in terms of water contact angle(CA), pure water flux(PWF), Fourier Transform Infrared Analysis(FTIR),pressure-responsive property, and pull-out strength. The morphologies of the membranes were investigated by scanning electron microscopy. We have characterized the foams from an intuitive point of view and demonstrated that the dimensional morphology of the membrane was closely related to isocyanate index. The result showed that the surface cell size of the PU sponge hollow fiber membrane gradually decreased with an increase of the isocyanate index. Due to the elasticity of PU at room temperature, the pressure responsive characteristic of the membrane was prepared. When isocyanate index was 1.05, the interface bonding strength of PU spongy hollow fiber membranes reached as high as 0.37 MPa, porosity and PWF were 71.5% and 415.5 L·m^-2·h^-1,respectively.

Improvement of Foaming and Emulsifying Properties of Gluten by Conjugation with Fructose through Maillard Reaction

Gluten has poor emulsifying and foaming ability due to its amino acid composition. In this study, Maillard reaction was used to improve the emulsifying and foaming properties of gluten. The processing conditions for the preparation of gluten-fructose conjugates were optimized by using Box-Behnken model to achieve optimum foaming and emulsifying activity, respectively.The results showed that glycated gluten exhibited enhanced emulsifying activity compared to native control. The processing conditions for the preparation of gluten-fructose conjugates with optimum emulsifying activity were as follows: the temperature was 48℃, reaction time was 72 h, and maltose/gluten(W/W) ratio was 125%. Under such condition, the average emulsifying activity was 66.54%, being improved by about 2.5 times compared with that of native control. The Foaming properties of gluten also increased significantly by glycation modification. The optimum conditions of response were as below: the temperature was 48℃, reaction time was 66 h, and maltose/gluten ratio(W/W) was 110%. Under such condition, the average foaming property was 158.57%, and it was three folds higher than that of the control.

Nanoparticle foaming agents for major gas fields in China

The conventional foaming agents have the problems of poor adaptability and high cost during the application in different types of gas fields,especially in high temperature,high salinity,high acidic gas and high condensate oil and gas fields.In this study,the Gemini foaming agent was used as the main agent to enhance foaming and foam stability of the foaming agent,the grafted nanoparticles were used as foam stabilizer to further improve the foam stability,and the characteristic auxiliaries were added to make the foaming agent suitable for different types of gas reservoirs.Two types and six subtypes of nanoparticle foaming agents have been prepared for the main gas fields of China.The experimental evaluation results show that the overall temperature resistance,salinity resistance,H2S resistance,CO2 resistance and condensate resistance of the nanoparticle foaming agents can reach 160℃,250000 mg/L,100 mg/L,100%and 40%,respectively.The new foaming agents have been used in 8685 wells in China.Compared with conventional foaming agent,the average gas flow rate per well increased by 62.48%,the pressure difference(casing-tubing)decreased by 18.9%,and the cost dropped by 45%.The effect of reducing cost and increasing efficiency is obvious.

Microstructure and Electrical Conductivity of CNTs/PMMA Nanocomposite Foams Foaming by Supercritical Carbon Dioxide

The carbon nanotubes（CNTs）/polymethylmethacrylate（PMMA）nanocomposite foams were prepared by the anti-solvent precipitation and supercriticalfoaming method.The morphology and the electricalconductivity of the foams with different kinds of CNTs were investigated.The experimentalresults showed that allthe foams had uniform cellstructure,and the cellsize changed from 1.9 to 10 μm when the foaming temperature ranged from 50 ℃ to 95 ℃.With smallcellsize（1.9-4.0 μm）,the conductivities of the foams were 3.34×10^（-6）-4.16×10^（-6） S/cm compared with the solid matrix since the introduction of micro cells did not destroy the conductive network.However,when the cellsize was biger（4.5-10 μm）,the aspect ratio of the CNTs played the dominant role of the conductivity.The foams with short CNTs had higher conductivity,since the short CNTs were hard to stretch and snap by the cells and can well-dispersed in the cellwalland celledges.The results of this work provided a novelmaterialdesign method for conductive foams based on the rule of both microstructure and aspect ratio of the CNTs.

Effects of ultra-high hydrostatic pressure on foaming and physical-chemistry properties of egg white

The influences of ultra-high hydrostatic pressure treatment on foaming and physical properties (solubility, hydrophobicity and sulfhydryl content) of egg white were investigated. A pressure range of 0-500 MPa, time range of 0-20 min and pH range of 7.5-8.5 were selected. The foaming property of egg white is improved by 350Mpa and 10min. The treatment resulted in in- crease of sulfhydryl content of egg white, while solubility and hydrophobicity were significantly decreased.

Preparation of Aluminum Foam Sandwich by Rolling-bonding/Powder Metallurgy Foaming Technology

Aluminum foam sandwich was prepared by rolling-bonding/powder metallurgical foaming technology, and the effects of rolling on bond strength of face sheet/powders and powder density were studied. Moreover, the foaming agent, TiH2, was heat treated and a certain amount of Mg was added into powder in an attempt to understand how the stability and uniformity of foam was improved. The experimental results show that the foaming precursors with ideal quality were obtained by rolling-bonding process. When rolling reduction is 67%, the consistency of powders reach to 99.87%. Throughout consideration of the bonding of face sheet/ core layer powders and deformation characteristic of powders, the optimum rolling reduction is 60%-70%. Cracks and drainage during foaming were inhibited by heat treatment of foaming agent TiH2 and the addition of a certain amount of Mg. The optimum heat treatment way of TiH2 is that heat preserving 1 hour at 450 ℃; the amount of adding Mg is 1wt%.

Foaming supramolecular surfactants for gas mobility control in naturally fractured carbonate reservoirs at high temperature,salinity,and hardness

Oil production and mainte nance are essential issues in naturally fractured reservoirs because they are the largest and most productive on earth.However,they present early water and gas channeling but could be remediated by using foaming agents to control these phenomena through blocking channeling areas.In Mexico these reservoirs have pressure up to 5,500 psi,high temperature up to 200℃,salinity up to400,000 ppm,and hardness up to 250,000 ppm;due to these thermodynamic conditions,there has been no available technology to form stable enough foams.In this work,a foaming supramolecular surfactant with the capability to chelate Ca^(2+)ions is examined.As a result,surfactant monomers are bridged by captured Ca^(2+)cations leading to the formation of high-molecular-weight oligomers,which significantly increment the viscosity of the solution improving the foam stability,and since at this manner the Ca2+cations are no longer available to precipitate as components of solid salts,the foaming supramolecular surfactant also performs as antiscalant.These observations are explained through quantum theoretical modeling.The foam is stable,effectively blocking the gas channels,whereas in presence of oil the foam is broken leading the oil to pass into the wellbore.The characteristic rheological properties of the foam allow its injection into the formation at a range of flow rates,foam qualities,and shear stress to achieve the flooding and the blocking of a variety of fractured carbonate formations,and the change of the wettability of the matrix,which is a desirable behavior in a huff and puff process,as reported in a previous publication about a successful pilot test of this foam.

Highly interconnected macroporous MBG/PLGA scaffolds with enhanced mechanical and biological properties via green foaming strategy

In this study,mesoporous bioactive glass particles(MBGs) are incorporated into poly(lactic-co-glycolic acid)(PLGA) to fabricate highly interconnected macroporous composite scaffolds with enhanced mechanical and biological properties via a developed supercritical carbon dioxide(scCO_(2)) foaming method Scaffolds show favorable highly interconnected and macroporous structure through a high foaming pressure and long venting time foaming strategy.Specifically,scaffolds with porosity from 73% to 85%,pore size from 120 μm to 320 μm and interconnectivity of over 95% are controllably fabricated at MBG content from 0 wt% to 20 wt%.In comparison with neat PLGA scaffolds,composite scaffolds perform improved strength(up to 1.5 folds) and Young's modulus(up to 3 folds).The interconnected macroporous structure is beneficial to the ingrowth of cells.More importantly,composite scaffolds also provide a more promising microenvironment for cellular proliferation and adhesion with the release of bioactive ions.Hopefully,MBG/PLGA scaffolds developed by the green foaming strategy in this work show promising morphological,mechanical and biological features for tissue regeneration.

Preparation of Controllable Cross-Linking Polyethylene Foaming Materials and Their Properties

In order to prepare the polyethylene materials with controlling properties,we developed two kinds of controllable cross-linking polyethylene foaming system.2,5-dimethyl-2,5-bis (tert-butyl peroxy) hexane was used as cross-linking agent and TEMPO as cross-linking inhibitor,azodicarbonamide (AC) was used as foaming agent and citric acid as foaming promoter.The density,expansion ratio,cellular structure and mechanical property of these two kinds of controllable materials were studied.Experimental results show that,properties of these two kinds of materials appear similar trend:cellular size and expansion ratio are enlarged with the amount of cross-linking inhibitor or foaming promoter increasing,while density and mechanical strength appear decreasing trend.Through comparing those two material systems’ properties,cross-linking polyethelene foaming system with citric acid as foaming promoter has better properties.

Slag foaming experiments in EAF for stainless steel production

The foaming slag practice can effectively solve the problems existing in EAF smelting of stainless steel, such as high electrical consumption ,high refractory consumption and long tap to tap time. In this paper, theoretical analyses were made on the technical difficulties and development feasibility of the technology. Slag foaming experiments were performed in a 10t EAF where crude stainless steel with a Cr content of 13% - 15% and a carbon content of 1.5% - 2.5% was smelted and special foaming pellets were added to release additional gas for better foaming. Good foaming slag was observed with the electric arc fully covered by the foam when the content of Cr2O3 is between 7% - 12%. The industrial scale experiments were performed in a 110 t EAF by the use of the same foaming pellets. Compared with the traditional operation, these experiments resulted in better foaming effects.

Numerical Simulation of Foaming Processes

The literature model studied in this article describes bubble formation and growth in a highly viscous polymer liquid with support of a gaseous matter dispersed under pressure before foaming. The foam growth is induced by the application of vacuum and mass transport of volatile components dissolved in the polymer liquid. Based on this literature model, aeration processes are calculated for intermediate viscosity and low viscosity biological systems, as they are of interest for biomatter foams, in particular for food foams in industrial processes. At the end of this article, the numerical results are presented and discussed.

Value of TCD foaming Test in Screening Patent Foramen Ovale in Migraine Patients and Efficacy of PFO Occlusion

Objective:To explore the effect of TCD foaming test in screening patent foramen ovale in migraine patients,as well as in the treatment effect.Methods:From September 2019 to August 2020,236 patients with migraine and 362 patients with normal physical examination were treated in our hospital.According to the random number table method,60 patients with migraine were selected as the observation group,and 60 patients with normal physical examination were selected as the control group.48 cases of PFO were confirmed by TCD foaming test Among the patients with migraine,36 patients received interventional occlusion therapy.The therapeutic effect and VAS score of the two groups were analyzed.Results:Through TCD foaming test,the proportion of PFO in the observation group was 80%,and that in the control group was 13.33%.The proportion of PFO in the observation group was significantly higher than that in the control group,and the difference was statistically significant(χ^(2)=53.5714,P<0.01);The symptoms disappeared in 30 patients and improved in 4 patients;Among the 36 patients who received interventional occlusion therapy,the VAS score of patients before and after the operation was significantly changed,and the proportion of patients whose pain disappeared after the operation was 83.33%,which was significantly lower than that before the operation,and the difference was comparable(χ^(2)=51.4286,P<0.01).Conclusion:TCD foaming test for PFO screening has strong applicability,not only safe and convenient,will not cause trauma to patients,and through interventional occlusion treatment,can significantly improve the clinical symptoms of migraine patients and cure patients.

Pollutant Sources and Foaming Control Measures of Decarbonization Solution in Natural Gas Purification Plant

Yanbei project of Schlumberger Copower Oilfield Engineering Co.,Ltd.-natural gas purification plant decarbonization unit is equipped with two sets of decarbonization systems(parallel operation).The two sets of systems adopt two tower process,full lean liquid circulation regeneration process,one tower absorption(absorption pressure 5.4mpag),one tower regeneration(regeneration temperature 95℃-110℃),purified natural gas carbon dioxide content≤2.5vol%,single set The treatment capacity is 2300 KM3/d.This paper introduces the problems existing in the decarbonization solution of the decarbonization unit in the natural gas purification plant in recent three years,analyzes the causes of pollutants affecting the quality of the decarbonization solution,and probes into the control measures for the pollution of the decarbonization solution,so as to provide reference.