Antifoam Research Articles

Freeze—Thaw Behaviours of Half Grouted Sleeve Connections with High-Performance Grout

Grouted sleeve connections with high-performance grout have superior mechanical properties at room temperature, but there is inadequate evidence to prove that they have good resistance to freeze—thaw effects. This paper presents a freeze—thaw experimental study on the tensile behaviour and bond behaviour of grouted sleeve connections with antifoaming agents, early strength agents, and expanding agents. First, the damage appearance, mass loss, and compressive strength loss were studied to determine the freeze—thaw damage mechanisms of grout with different admixture contents, and three optimal composition ratios were chosen for further study. Then, grouted sleeve connections were subjected to tensile tests after different freeze—thaw cycles, and the damage modes and damage mechanisms were studied. The tensile strength of pure rebar was predicted to increase linearly with the number of cycles. For the rebar fracture specimens, the tensile strength of grouted sleeve connections was mainly derived from the tensile strength of the pure rebars and increased linearly with the number of cycles. The experimental results may provide a significant reference for grouted sleeve connections under freeze—thaw conditions.

Effect of oral simethicone on the quality of colonoscopy: A systematic review and meta-analysis of randomized controlled trials.

In this systematic review and meta-analysis, we aimed to investigate the effect of oral simethicone (SIM), an antifoaming agent, on the quality of colonoscopy in terms of bowel preparation quality, adenoma or polyp detection rate (ADR/PDR) and cecal intubation rate (CIR). All randomized controlled trials (RCTs) on the use of SIM during bowel preparation for colonoscopy published up to 17 March 2021 were identified from the PubMed, EMBASE and Cochrane Library databases. Bowel preparation quality, ADR/PDR/CIR, cecal intubation time (CIT), withdrawal time (WT), patients' tolerability, acceptability and volume of foam and bubbles were compared between the SIM and non-SIM groups. Thirty-eight RCTs with 10 505 patients were included. Oral SIM significantly increased the rate of total Boston bowel preparation scale (BBPS) score ≥6 (risk ratio [RR]1.13, P < 0.0001), acceptability (RR1.15, P=0.01) and the rate of no or minimal foam and bubbles (RR1.28, P < 0.00001) and decreased abdominal distension (RR0.64, P < 0.0001). However, it had no significant impact on overall ADR, overall PDR, CIR, CIT or WT. The rate of total BBPS score ≥6 remained significantly higher in the SIM group when a single-dose laxative regimen or a SIM dosage of ≥320 mg was employed; and ADR, PDR and CIR were significantly increased in the SIM group among colonoscopy clinicians who achieved an ADR <31%, PDR <45% and CIR <96%, respectively. Oral SIM can improve bowel preparation quality, especially in patients receiving a SIM dosage of ≥320 mg or a single-dose laxative regimen. SIM may be preferred by junior colonoscopy physicians/trainees with a lower ADR/PDR or CIR.

Preparation of Magnesium Ammonium Phosphate Mortar by Manufactured Limestone Sand Using Compound Defoaming Agents for Improved Strength and Impermeability

Magnesium ammonium phosphate cement (MAPC) mortar has recently risen up as high performance rapid repair material for concrete structures. But high costs of the raw materials limit its restoration and maintenance projects on a wide application range. This study proposes the use of manufactured limestone sand with lower cost and wider range of sources in replacement of quartz sand as fine aggregates to produce MAPC mortar. However, the limestone fines of manufactured sand were initially found to have negative effects on the performance of MAPC mortar, causing significant blistering and volume expansion and decreased compressive strength and interfacial bonding strength. To minimize these negative effects, polyether modified silicone (PMS) defoamer and its compound use with mineral admixtures Portland cement and silica fume were investigated on the effectiveness in reducing expansion and improving other properties of MAPC mortar. Results showed that the compound use of PMS defoamer and Portland cement as a new defoaming formula effectively reduced the volume expansion from 7.92% to 0.91%. The compressive strength and interfacial bonding strength were significantly improved by over 34% and 60% respectively. Moreover, this defoaming formula showed improvements in water-tight performance and resistance to chloride penetration. According to the mercury intrusion porosimetry (MIP) analysis, the total porosity of MAPC mortar after defoaming treatment was decreased by about 40% and the pore structure was also modified to be finer by significantly reducing the harmful macropores. Overall, the use of manufactured limestone sands as fine aggregates turned out to be a feasible and economic approach for promoting the filed application of MAPC mortar.

Occurrence and distribution of organophosphate flame retardants in seawater and sediment from coastal areas of the East China and Yellow Seas

Organophosphates (OPEs) are manmade organic pollutants that are widely used as flame retardants, plasticizers, and antifoaming and hydraulic agents. In this study, seven OPEs in seawater and sediment from the Yellow Sea and East China Sea were determined to study the distribution and diffusion behavior, and to evaluate the environmental risks. The ΣOPEs in the seawater and sediments ranged from below the method detection limit (<MDL) to 497.40 ng/L and from < MDL to 66.50 ng/g dw, respectively. Tri-n-butyl phosphate (TnBP), tris-(1, 3-Dichloro-2-Propyl) phosphate (TDCPP), and tri-meta-cresyl phosphate (TmCP) were the dominant OPEs in the seawater and sediments. OPEs were mainly distributed in coastal areas and the South Yellow Sea, indicating that they are mainly affected by land-based pollution and ocean currents. Fugacity analysis shows that tri-para-cresyl phosphate (TpCP) was in a state of equilibrium, while TDCPP, TnBP, and TmCP other OPEs tended to diffuse from sediment to water. The diffusion behavior of OPEs is mainly affected by their chemical properties. Hazard quotient (HQ) values of TmCP and TpCP in sediment samples were >1.0, indicating high ecological risks to aquatic organisms.

Reviewing use of simethicone in gastrointestinal endoscopy

Ulrike Beilenhoff reconsiders endoscopic use of the defoaming agent simethicone in light of evidence that it may leave residue in the endoscope that is resistant to reprocessing, facilitating the growth of micro-organisms and biofilms and compromising patient safety

Characterization of selected plant seed oils as anti-foam agents in natural gas treatment units

Characterization of selected plant seed oils as anti-foam agents in natural gas treatment units

Considerations on the Analysis of E-900 Food Additive: An NMR Perspective.

Food additives are in widespread use in the food industry to extend the shelf life of food, improve its organoleptic characteristics or facilitate industrial processing. Their use is not without controversy, which makes regulation and control crucial for food safety and public health. Among food additives, silicone-based antifoaming agents (polysiloxanes or E900) are difficult to analyze and quantify due to their polymeric nature. Currently, there is no official method of quantifying this additive in foods. In this context, nuclear magnetic resonance (NMR) is a quantitative method for speciation analysis of silicon compounds almost without known interferents. In this work, we describe the evolution of the regulation of the E900 additive, discuss different analytic methods quantifying polydimethylsiloxanes (PDMS), and propose a new method based on NMR suitable for analyzing the content of E900 in the form of PDMS in various types of food from dietary oils to marmalades and jellies, among others. The proposed method consists of a previous quantitative concentration of PDMS by liquid–liquid extraction and the monitoring of the quantification using a bis(trimethylsilyl)benzene (BTMSB) standard to control the variability, ranging within 2–7%, depending on the food. This simple, direct, and reproducible procedure for aqueous and lipidic foods may help to monitor and fill a gap in regulatory legislation regarding the E900 additive.

Analysis of the Physicochemical Properties of Some Selected Non-Edible Vegetable Oil-Based Cutting Fluids Using the Design of Experiment (DOE) Approach

The pursuit of environmentally friendly cutting fluids is ongoing as the problems of traditional cutting fluids become more apparent. The bulk of vegetable oils used in studies are consumable and, if marketed, may conflict with human utilization, making cutting fluids more costly. However, few investigations on the use of lesser-known vegetable oils as cutting fluids have been conducted. As a result, the goal of this research is to examine how effective some lesser-known vegetable oils will be if used as a cutting fluid. Based on some physicochemical properties such as acid value and viscosity, the developed vegetable oil-based cutting fluids (watermelon and jatropha) were statistically analyzed using 24 full factorial techniques. This paper aimed at determining the interaction of the physicochemical properties on the developed cutting fluids. Emulsifiers, antifoam agents, biocide, and anti-corrosive agents were considered as natural variables. The effect of the natural variables on the acidity index and viscosity of cutting fluids were fully analyzed with ANOVA, contour, and surface plots. From the responses obtained from the experiment as explained by the independent variables (emulsifying agent, anti-corrosion agent, biocide, and antifoam agent), the watermelon seed oil-based cutting fluid was 89% accurate, while the jatropha oil-based cutting fluid was 75% accurate.

Experimental study on combustion and unregulated emission characteristics of a diesel engine fueled with light hydrocarbon/diesel blends

Rigorous emission regulations are provoking to pursue substitute of diesel with clean and sustainable alternative fuels to work out the problem of the regulated and unregulated emissions and diesel depletion. In this paper, the partial load characteristics of emission especially unregulated and combustion characteristics of a six-cylinder compression ignition diesel engine fueled with conventional diesel and 85% light hydrocarbon (LHC)-diesel blends were investigated and compared at the load points of 50%, 75% and 100% and the speed of 1000 rpm. Gas chromatography-mass spectrometry (GC–MS) technology was utilized to identify components of both tested fuel and unregulated emissions. The cylinder pressure, pressure rise rate, indicated power, heat release rate and emissions were comparatively analyzed between these two fuels. The gaseous pollutants including NOx, CO and total hydrocarbon (THC) are determined by gas analyzer. Based on the experimental results, blending LHC extend the ignition delay period, thus leading to its combustion phase lag behind that of diesel fuel by 3°CA. Significant reduction in specific NOx and CO emissions was noted while THC emission is higher in engine fueling LHC/diesel blends. The dominant unregulated pollutants primarily include organosilicon compounds (OSC), aromatic compounds (AC), and non-aromatic hydrocarbons and their derivatives (NAHC). The determinant factors on OSC emissions are summarized into the content of antifoaming agents in lubricants and the load conditions. The AC emissions of both fuels have an ascending tendency with the increase of load and the AC emissions of LHC/diesel blends are obviously less than that of pure diesel. The NAHC emissions usually appear under higher load conditions with regard to LHC blends and the content is far lower than that of diesel. In a word, blending diesel with LHC significantly contributes to improve both combustion and emission characteristics.

Effects and Mechanisms of Foam Suppression in Food Waste Anaerobic Digester Using Defoaming Agents

Effects and Mechanisms of Foam Suppression in Food Waste Anaerobic Digester Using Defoaming Agents

A Study on the Manufacture and Physical Properties of Liquid Adhesive for Wood Preservation - Focusing on the Synthesis of Gelatin and Carrageenan -

In order to improve the usability of glue, a traditional adhesive material, and the gelation process of seaweed extract carrageenan, a liquid adhesive for wood preservation was prepared by mixing the two materials. The prepared wood adhesive was mixed with a 15 wt% aqueous solution of glue, λ-carrageenan, an antibacterial agent, an antifoaming agent, and the maximum adhesive strength of 1.80 Mpa was confirmed. As a result of comparison, the adhesive strength was superior to that of 5 different types of traditional natural adhesive ingredients (aqueous solution) and 1 type of polyvinyl acetate-based adhesive.

PHYSICOCHEMICAL PROPERTIES OF SULPHATE WASTE LIQUOR AFTER SOAP EXTRACTION IN THE PRESENCE OF SURFACTANTS

During the wood delignification a multicomponent spent liquor (black liquor) is formed. Depending on the type of wood, black liquor is enriched with valuable extractives. The isolation of extractives from processing liquors and their conversion into biologically active substances, tall products is according to development trend of pulp and paper industry. It includes the introduction of scientific based technologies in manufacturing processes with reference to modern environmental protection requirements. Now the extraction efficiency of sulphate soap does not exceed 75–80% whereby the quality of obtained soap is low. Sulphate soap, especially extracted after hardwood cooking, contains a large amount of impurities. This complicates the process of soap treatment into valuable biologically active substances (beta-sitosterol, etc.). &#x0D; In the present work the addition of demulsifying and coagulating substances into the black liquor is proposed to intensify the hardwood sulphate soap extraction. The chemical colloidal characteristics of the obtained sulphate soap were investigated. Two critical micelle concentration (CMC) were found on the surface tension isotherms. The second critical micelle concentration (CMC2) in the concentration range of 0.9–1.0% CMC2 indicates the restructuring of micelles into a spherocylindrical shape. A comparative qualitative and quantitative analysis of the composition of sulfate soap obtained in industrial conditions and in the presence of selected additives in laboratory was carried out. Surfactants promote the extraction of phytosterol from black liquor obtained from hardwood species cooking. The influence of surfactant addition on the main physical and colloidal chemical characteristics of black liquor before and after isolation of sulphate soap is investigated. A decrease in viscosity and a de foaming of a black liquor solution is observed as a result of the addition of surfactant additives.

Fatty alcohol polyoxyethylene ether sulfonate for foam flooding in high-salinity and high-temperature reservoir conditions

Foam flooding can significantly improve the sweep efficiency of gas flooding by avoiding or weakening gas segregation, viscous fingering and gas channeling through areas of high permeability. However, most conventional anionic surfactants are not suitable to be used as foaming agents due to low tolerance to either high salinity or high temperature. In this paper, an anionic-nonionic combined surfactant, fatty alcohol polyoxyethylene (3) ether sulfonate (AEO3-HS) was synthesized, and its foaming performances at different conditions were examined. The results show that the foaming performance of the AEO3-HS is sensitive to crude oil which behaves as a defoaming agent. But this can be improved by mixing with cetyl dimethyl hydroxypropyl sulfobetaine (C16HSB). In mild reservoir conditions such as dissolved in simulated Daqing connate water (45 ℃, total salinity of 6778 mg/L, pH = 8–9) the AEO3-HS/C16HSB binary mixture at an optimal mole fraction ratio (0.6/0.4) and an optimal total concentration (4 mM) gives the maximum composite foaming index of 1100 Ls by shaking 10 mL solution with 0.25 g oil in a 100 mL cylinder. Moreover, the AEO3-HS/C16HSB binary mixture is well soluble in brine with 5000 mg/L CaCl2 + 100,000 mg/L NaCl at 60 °C, and does not hydrolyze in aqueous solution when stored at 90 °C for 3 months. In addition, the AEO3-HS and C16HSB molecules show attraction in mixed monolayer and the crude oil can be easily emulsified as small oil droplets dispersed in foaming solution during foaming process, which ensures the stabilization of the pseudo-emulsion films and thereby the foam stability in the presence of crude oil. The AEO3-HS synthesized is therefore a good candidate as foaming agent for high salinity and high temperature reservoirs.

Optimal Timing of Simethicone Supplement for Bowel Preparation: A Prospective Randomized Controlled Trial.

Background and Aims Simethicone (SIM), as an antifoaming agent, has been shown to improve bowel preparation during colonoscopy. However, the optimal timing of SIM addition remained undetermined. We aimed to investigate the optimal timing of SIM addition to polyethylene glycol (PEG) to improve bowel preparation. Methods Eligible patients were randomly assigned to two groups: the SIM evening group (SIM addition to PEG in the evening of the day prior to colonoscopy) and the SIM morning group (SIM addition to PEG in the morning of colonoscopy). The primary outcome was Bubble Scale (BS). The secondary outcomes were Boston Bowel Preparation Scale (BBPS) and adenoma detection rate (ADR). Results A total of 419 patients were enrolled in this study. The baseline characteristics of the patients were similar in both groups. No significant differences were observed in terms of BS (8.76 ± 0.90 vs. 8.65 ± 1.16, P = 0.81), ADR (34.1% vs. 30.8%, P = 0.47), Boston Bowel Preparation Scale (BBPS) (8.59 ± 0.94 vs. 8.45 ± 1.00, P = 0.15), and withdrawal time (8.22 ± 2.04 vs. 8.01 ± 2.51, P = 0.094) between the two groups. Moreover, safety and compliance were similar in both groups. However, the SIM evening group was associated with shorter cecal intubation time (3.80 ± 1.81 vs. 4.42 ± 2.03, P < 0.001), higher BS (2.95 ± 0.26 vs. 2.88 ± 0.38, P = 0.04) in the right colon, and diminutive ADR (62.5% vs. 38.6%, P = 0.022) in the right colon, when compared to the SIM evening group. Conclusions The SIM addition to PEG in the evening of the day prior to colonoscopy can shorten cecal intubation time and improve BS scores and diminutive ADR of the right colon compared with the SIM addition to PEG in the morning of colonoscopy in bowel preparation.

Occurrence and Partition of Organophosphate Flame Retardants in Seawater and Sediment from the Coastal Areas of East China and Yellow Sea

Organophosphates (OPEs) are manmade organic pollutants that are widely used as flame retardants, plasticizers, and antifoaming and hydraulic agents. In this study, seven OPEs in seawater and sediment from the Yellow Sea and East China Sea were determined to study the distribution and diffusion behavior, and to evaluate the environmental risks. The ΣOPEs in the seawater and sediments ranged from below the method detection limit ( 1.0, indicating high ecological risks to aquatic organisms.

Formation and stability of oil-in-water emulsions based on components of bioprocesses: A microfluidic analysis

Undesirable oil-in-water (O/W) emulsions are typically developed and stabilized during biotechnological processes, hampering the recovery of oil-based bioproducts. Such emulsions emerge in the fermentation medium due not only to the process conditions, but mainly to the broth composition. In this light, an in-depth study of the formation and stability of these colloidal systems is paramount to establish an appropriate formulation, especially considering some highly relevant components for bioprocesses (such as antifoams). In general, antifoams are added to the fermentation broth with little control, although they can potentially lead to the formation of undesirable emulsions. In this context, we analyzed O/W emulsions stabilized by yeast cells and two widely used antifoaming agents (Pluronic L81 and Antifoam C) within microfluidic glass capillaries to perform a high-throughput analysis and reveal the role of these components in the formation of stable emulsions. In general, both antifoams and yeast cells enabled the formation of droplets depending on the characteristics of the oily phase, but marked differences were observed in the stability of the formed emulsions. For instance, Pluronic L81 allowed the formation of a highly stable emulsion, while Antifoam C produced droplets more susceptible to destabilization. Such results indicate that a particular choice of the pair antifoam-oily phase can facilitate the destabilization process and even impair the mechanism of droplet formation.

Effect of the compounding of an antifoaming agent and a viscosity modifying agent on the frost resistance of mold bag concrete

Channel lining mold bag concrete in the cold area of ​​northern China needs to achieve high frost resistance under the conditions of large fluidity and low strength grade. However, the extensive use of a high range water reducer (HRWR) and an air entraining agent (AEA) brings about the problems of a large air content loss, a large fluidity loss and many harmful big bubbles to fresh concrete, reducing the pumping performance and frost resistance of mold bag concrete. In this study, the effects of compounding an AEA, an antifoaming agent (AFA), and a viscosity modifying agent (VMA) on the workability, mechanical properties and frost resistance of concrete are studied by using the response surface methodology (RSM). The results showed that AEA and AFA were significant factors that affected the relative dynamic elasitic modulus. The interaction of AFA and VMA on the relative dynamic elasitic modulus was significant. The compounding of AFA and VMA achieved the effects of synergistically improving the workability, air-void structure and frost resistance of concrete. When the dosage of AEA was 0.0055%, the compounding of AFA and VMA synergistically reduced the air content loss rate by 42.30%, reduced the slump flow loss rate by 47.29%, reduced the number of large bubbles by 57.96%, increased the number of fine bubbles by 16.55%, reduced the spacing factor by 18.09%, increased the specific surface area by 41.16%, increased the relative dynamic elasitic modulus by 16.11%. Using RSM optimization and validation, an optimal mix proportion for mold bag concrete with a desirability of 0.998 was proposed to be the following: AEA of 0.006%, AFA of 0.176%, and VMA of 0.019%.

Улучшение технологических индикаторов полуфабрикатов производства сахара из бактериально инфицированной сахарной свеклы

Introduction. Technological aids play a special role in sugar production technology, but their complex effectiveness requires a comprehensive and in-depth study. The research objective was to establish the patterns of change in the technological indicators of semi-finished products obtained from bacterially infected sugar beets with the combined use of an enzyme preparation, antimicrobial agent, and defoamer.&#x0D; Study objects and methods. The study involved such semi-finished products as juice (diffusion, pre-defecated, first and second saturation) and syrup, the quality of which was determined according to standard methods. The laboratory experiment was carried out on the basis of the second-order D-optimal Box-Behnken plan for three factors at three levels.&#x0D; Results and discussion. The research revealed positive dynamics of the following technological indicators: sucrose content, deposition rate, turbidity, chromaticity, and general purification effect. The sugar beet had the second degree of infection with mucous bacteriosis. Purified juice underwent lime-carbon dioxide purification and thickening under the combination of enzyme preparation Dextrasept 2, antimicrobial agent Betasept, and antifoam agent Voltes FSS 93. The greatest increase in sucrose at the level of 1.1% by DM weight was confirmed by a higher overall effect of purification of diffusion juice (2.2 %). The values of turbidity of the purified juice and syrup were below the threshold values. The low values resulted from the increase in the sedimentation rate of the pre-defective juice and the juice of the first saturation by an average of 4.1 and 3.2 times, respectively, due to the effective removal of high molecular weight compounds. The share of the enzyme preparation was 40–71%, antimicrobial agent – 19–49%, defoamer – 1.6–6.5%. The values of the multicriteria optimization parameter corresponded with technological indicators. The optimal combination (per 1000 tons of beets) included 6–8 kg of Dextrasept 2, 1.5–2.0 kg of Betasept, and 15–20 kg of Voltes FSS 93. As a result, the yield of white sugar increased by 0.25%. &#x0D; Conclusion. The regression dependencies can be recommended for predicting the main technological indicators of semi-finished products. The resulting data makes it possible to determine the effectiveness of the combined use of an enzyme preparation, antimicrobial agent, and defoamer in sugar production. Further research will identify the patterns of multifactorial interaction of these preparations.

Evaluation of Filter Cake Oil as Antifoam in Yeast Production: New Use for this By-Product of the Sugarcane Derivatives Industry

Fodder yeast is obtained in an aerobic fermentation process where foaming is a major problem to be solved. In this article, the antifoam property of crude and purified filter cake oil is evaluated in order to use this residual as an alternative to replace the import of commercial antifoam agents and to reduce the production costs of fodder yeast. Knock down test and the comparisons with two commercial antifoam agents were done. Blackstrap molasses medium at 20 and 40 g/L of total reducing sugar was used. All products were studied in their pure form and commercial ones also in dilutions 1:2 and 1:5 v/v. Hansen's solubility parameters (HSPs) to analyze the affinity of each defoamer for yeast were determined. It was obtained the crude and purified filter cake oil showed similar behavior to commercial defoamers with an immediate antifoam effect, removing between 40 and 60% of the initial foam at both sugar concentrations in the first 5 min. The regression model for both medium concentration showed purified filter cake oil has the greatest knockdown effect (Ca = 57.00 and 74.11) and with greater foam suppression stability the commercial defoamer Quimifoam Máster (Cb = − 1.05 and − 1.51) respectively. Ra values obtained in HSPs test, indicated the affinity of defoamers to the medium. Purified filter cake oil is an effective product for its use as an antifoam with the best knock down effect for both concentrations of sugars in the medium. The determination of HSPs corroborates the effectiveness of this product to suppress foam.

Causes and Control Technology of Slurry Overflow in an Ammonia Desulfurization Tower.

In the flue gas ammonia desulfurization process of the coal chemical industry, ammonium sulfate slurry in the desulfurization tower often foams and overflows, which wastes resources and pollutes the environment. The solution to this problem remains largely unknown. This paper aims to reveal the causes of foaming by analyzing foam composition, ammonia desulfurization process raw material source, and characteristics of the flue gas source of the coal chemical industries. It is seen that the organic carboxylate ammonium salt surfactant in the slurry was the main cause of ammonium sulfate slurry foaming. Moreover, due to ammonium sulfate crystals and ash in foam forming a skeleton to support the foaming structure, the foam was not easy to break. More importantly, an appropriate defoaming agent was screened and optimized by an ammonia desulfurization tower simulated device in the laboratory. The YLZ-3 compound defoaming agent, with the optimal defoaming efficiency, was obtained by combining a polyether siloxane copolymer, n-octyl alcohol, fumed silica, and deionized water. It had a good temperature stability and little influence on the ammonium sulfate slurry drying time. However, defoaming agent addition could affect the ammonium sulfate crystal form. The foam overflowing could be controlled by spraying the defoaming agent from the top of the tower. Thus, the problem of bubbling overflow of the ammonia desulfurization tower could be resolved very well.