Surface Tension Of Water Research Articles

Experimental study on ventilated cavity flow at the tail of underwater vehicle under low surface tension

In model experiments, the Weber number determined by the surface tension usually has a significant effect on the ventilated cavity flow characteristics. This paper describes experiments in which the surface tension of water is reduced by adding surfactant, allowing thes flow characteristics of the ventilated cavity at the tail of an underwater vehicle under low surface tension to be analyzed. The effects of the Froude number, Weber number and cavitation number on the development of the ventilated tail cavity are explored. There are three stable closure modes of the ventilated cavity under low surface tension, namely, a complete foam cavity, partial foam cavity, and giant spindle cavity. The results show that a larger Froude number produces a smaller ventilated cavity, which mainly exhibits the complete foam cavity closure mode. A smaller cavitation number creates a larger ventilated cavity, which is mainly represented by the giant spindle cavity closure mode. The critical cavitation number under this closure mode is 2.19. At higher ventilation pressures, the entrainment ability at the end of the ventilated cavity is stronger, and bubbles are less likely to fall off.

Numerical Investigation on EOR in Porous Media by Cyclic Water Injection with Vibration Frequency

Water injection with an oscillatory pressure boundary is a promising technology, which can achieve a more economical and environment-friendly EOR (enhanced oil recovery). However, due to the unclear critical injection frequency, its oil production performance has been unstable and is far from reaching the optimal level. Here, a numerical model is established for oil recovery by the water injection with the oscillatory boundary condition to find out the critical frequency for the optimal EOR. The correlations between the water injection frequency and the EOR level at diverse oil–water surface tensions and oil viscosities are integrated into the model. Our numerical model reveals that an optimal EOR of roughly 10% is achieved at the critical water injection frequency compared with water injection without an oscillatory boundary. The EOR mechanism is revealed showing that upon water injection with the optimum frequency, the formation of the preferential pathways is inhibited and the pressure transmits to the wall sides to displace the oil. Moreover, it is indicated that the required critical frequency increases with higher surface tension and larger oil viscosity. In addition, the difference between the residual oil saturation at the optimal frequency increases with the increase in surface tension compared with water injection without an oscillatory boundary. Last but not least, it is elucidated that at a constant injection frequency, a higher EOR is achieved when the water–oil surface tension is lower but the oil viscosity is larger. Our work promises economic, eco-friendly and controllable enhanced oil recovery.

Behavior of Auramine O in the Aqueous Solution of Two Kolliphors and Their Mixture

The studies on the behavior of Auramine O (AuO) at the water-air interface and in the bulk phase of the aqueous solution of Kolliphor® ELP (ELP) and Kolliphor® RH 40 (RH40) and their mixture were based on the results obtained from the measurements of the contact angle of water, formamide and diiodomethane on the polytetrafluoroethylene covered by the AuO layer, the surface tension of the aqueous solution of AuO, AuO + ELP, AuO + RH40, AuO + ELP + RH40, density and fluorescence intensity. Based on the obtained results, it was possible to determine components and parameters of the AuO surface tension, concentration and composition of the mixed monolayer, including AuO, ELP and RH40, as well as that of the mixed micelles, and to determine the Gibbs standard free energy of adsorption, micellization and AuO solubilization. The obtained results also showed that surface tension isotherms of the studied solutions can be described by the Szyszkowski equation and the exponential function of the second order and predicted by the Fainerman and Miller equation. In addition, the mixed surface layer composition can be predicted based on the contribution of the components of this layer to the water surface tension reduction.

Microbial conversion of agro-processing waste (peanut meal) to rhamnolipid by Pseudomonas aeruginosa: solid-state fermentation, water extraction, medium optimization and potential applications

The high cost and severe foam in rhamnolipid fermentation are still bottlenecks for its industrial production and application. Non-foaming production of rhamnolipid by Pseudomonas aeruginosa FA1 was explored in solid-state fermentation using the agro-processing waste (peanut meal) as low-cost substrate. An environmental-friendly extraction method was developed to harvest rhamnolipid from solid-state culture. Strain FA1 produced 265.4 ± 8.2 mg rhamnolipid using 10 g peanut meal. HPLC-MS results revealed that 7 rhamnolipid homologues were produced, mainly including Rha-C8-C10 and Rha–Rha-C10-C10. Nitrate was the optimal nitrogen source. Peanut meal, MgSO4 and CaCl2 were significant factors for rhamnolipid production in solid-state fermentation. Rhamnolipid production was enhanced 31 % using the solid-state medium optimized by response surface method. The produced rhamnolipid reduced water surface tension to 28.1 ± 0.2 mN/m with a critical micelle concentration of 70 mg/L. The crude oil was emulsified with an emulsification index of 75.56 ± 1.29 %. The growth of tested bacteria and fungi was inhibited.

ВПЛИВ Zn2+ ВОДНОГО СЕРЕДОВИЩА НА ДОБОВУ ЦИКЛІЧНІСТЬ ДИХАННЯ АЛОВИДІВ PLANORBARIUS CORNEUS S. L. (MOLLUSCA, GASTROPODA, PLANORBIDAE)

We investigated the impact of the different concentrations of Zn2+ in the water (in the 0.5 MPL – 3 MPL range) on the chronological features of lung and direct diffusive respiration in representatives of superspecies complex of ramshorns Planorbarius corneus s. l. (“eastern” and “western” allospecies) from the Ukrainian river network. They have a bimodal respiration. Atmospheric oxygen goes into their true lungs through the breathing pore – pneumostome, – during the periodical rises up to the water surface tension film. And the oxygen soluble in the water is acquired by the osmosis through the epithelial body coverings and the surface of adaptive gill. Both ways are almost equally important for the oxygen supply of mollusks’ organisms.
 Zn2+ ions are the powerful toxins of local effect for ramshorns. The excess of the MPL may lead to the impairment of stable homeostasis. Both P. corneus allospecies s. l. have clearly expressed diurnal cyclicality of their lung respiration (in the “day-night” rhythm). They perform 1.2–1.3 times more “inhales” during the day with the shorter (1.3–1.4 times) intervals. This apparently is the consequence of physiological activity increasing in the period of their most intensive life-giving metabolic processes occurring. 
 Under the 0.5 MPL of Zn2+ there were no statistically significant changes in lung and direct diffusive respirations indexes (comparing to the control) in both allospecies during the latent phase of their intoxication process. “Inhales” during the day were 1.1 time longer than during the night in experimental animals. This let mollusks replenish the amount of oxygen they underreceived due to the decreased number of night “inhales”.
 Under MPL Zn2+ level the respirational indexes of ramshorns (number, length and volume of “inhales” and intervals between them) increased in average 1.1 times. Their feeding and moving behaviors visibly activated, which promoted the increasing of the daily frequency of their respiration rhythm. Under the 2 MPL concentration of Zn2+ there was further significant increasing (p

Synthesis, Self‐Aggregation, Interfacial Behavior and Interaction Studies of Non‐ Cytotoxic Caffeinium‐Based Surface Active Ionic Liquids with Sodium Dodecyl Sulfate

Caffeinium-based surface-active ionic liquids (SAILs), (1-(2-alkanoyl oxy) ethylcaffeinium bromide), [CnEcaf]Br with variable chain length (n=12, 14, 16) were synthesized and their molecular structures were explored by multiple spectral techniques. The critical micelle concentration (CMC) of pure SAILs and their mixtures with sodium dodecyl sulfate (SAIL-DS) in aqueous solution was determined by employing various techniques at 298 K. The tensiometry and dynamic light scattering (DLS) techniques have been employed to gain insight about the interfacial behavior and aggregate size of cat-anionic mixtures in aqueous solution. Interestingly, the interaction parameters ( ) showed strong synergism between these two oppositely charged molecules. Further, it was found that SAIL-DS cat-anionic mixtures exhibit excellent adsorption efficacy and are more effective in lowering the surface tension of water as compared to pure SAILs. The DLS results showed the formation of mixed-size aggregates in SAIL-DS systems. The contact angle and wetting properties of pure SAILs over the parafilm surface were also determined using a static sessile drop method. Further, MTT assay was used to determine the biocompatibility of SAILs on Human embryonic kidney (HEK-293) cell line and in-vitro anti-cancer activity on Lung cancer cells (A549). These SAILs displayed substantial cytotoxicity against cancerous cells, indicating that they could be useful in a variety of biological applications.

Assessment of bacterial biosurfactant production and application in Enhanced Oil Recovery (EOR)—A green approach

The present work attempts to investigate production of biosurfactant, in a modified synthetic media, by less explored bacterial strain isolated from iron factory waste effluent from West Bengal, India and its application in enhanced oil recovery operations. The screened isolate was identified to be Pseudomonas mendocina by 16s rDNA gene homology (NCBI-Genebank accession no. MH091331). It showed a high emulsification of 68.3 ± 2.86%, lowering surface tension of water to 31 mN/ m and CMC of 125 mg l −1 and found to be alkalophillic (pH 6 to 12) and halophilic (up to 6% NaCl) in nature. Batch study in optimized media led to maximum yield of 3.09 ± 0.12 g l −1 . Production kinetic analysis by Luedeking Piret model successfully predicted mixed growth associated biosurfactant production with α and β values of 0.73 and 1.60 respectively and a yield coefficient of 0.82. Cost estimation for production of biosurfactant was calculated under lab scale conditions. Characterization of the extracted biosurfactant by anthrone test and Lowry’s protein estimation, TLC, FTIR, H 1 NMR and FESEM revealed the presence of sugar, peptides and lipid moieties. The biosurfactant obtained is extremely robust with high stability, sustaining wide range of pH (4 to 12), salinity (0.5 to 10% NaCl) and temperature (up to 100 °C). Toxicity assessment by Vigna radiata seed bioassay and MTT assay using and HEK293 cell line showed the non-toxic nature of the biosurfactant. Crude biosurfactant could play effective role in oil recovery with 44.3 ± 0.5 % enhanced oil recovery using sand packed column. • Biosurfactant (BS) from newly isolated halo-alkalophillic bacterial strain. • BS production in economically suitable optimized media. • Notably stable BS, tolerating extreme physiological conditions. • BS exhibiting presence of both glycolipids and lipopeptides: blend nature. • Potential use of crude biosurfactant for enhanced oil recovery.

Surfactants-surface active agents behind sustainable living

Abstract Surfactants are surface active agents. They are mainly chemicals, when added to water will reduce the surface tension of water and thus increases wettability on the given surface. Surfactants normally carry hydrophilic and hydrophobic ends among which hydrophilic end connects to water layer. The hydrophobic part connects between aqueous phase and the given hydrophobic surface through the hydrophobic end. However, these surfactants act as emulsifying agents or foaming agents. Further the chemistry behind the action of surfactants is introduced for the readers. Surfactants can be classified based on origin, charge on heads, solubility of water etc. and is specified in this paper. Also synthesis of various types of surfactants is carefully incorporated in the chapter. The chapters dwells in detail the various sustainability related applications of surfactants which is relevant for sustainable living in the society.

Utilizing of Magnetized Water in Enhancing of Volcanic Concrete Characteristics

Volcanic concrete is an eco-friendly concrete type in that it contains coarse and fine aggregates that all extracted from the igneous volcanic rock. However, utilizing of volcanic ash (VA) as partial/full replacement of concrete cement significantly affects the concrete workability, especially at high cement replacement ratios. This has also some adverse effects on concrete strength. Utilizing magnetized water (MW) in concrete as a partial/full replacement of ordinary tap water (TW) has a notable effect on enhancing the fresh and hardened concrete properties. This research aims to study the effect of using MW prepared in a magnetic field of 1.4 Tesla on the workability and hardened properties (compressive, tensile, and flexural strengths) of volcanic concrete. In this study, VA partially replaced volcanic concrete cement with ratios of 5%, 10%, 15%, and 20%. Ten volcanic concrete mixes were prepared in two groups. The first one was prepared with VA (0–20%) and mixed with TW. The other group was prepared with the same VA contents like group one, but mixed with MW. Microstructure imaging for volcanic concrete was also conducted in this study. Results of water tests showed 17% and 15% increase in total dissolved solids (TDS) and pH, respectively, of MW compared with those of TW. In addition, the water magnetization decreased the water surface tension by 7% compared with that of TW. Results of hardened concrete tests showed that the best ratio of VA in volcanic concrete was 5% with and without using magnetized water. The volcanic concrete slump decreased when using TW; however, using MW enhanced the volcanic concrete slump by up to 8%. The compressive strength was improved by 35%, 23%, and 20% at 7 days, 28 days, and 120 days, respectively, with no VA and with the presence of MW. The compressive strength was improved by 11%, 12%, and 11% after 7 days, 28 days, and 120 days, respectively, with using 5% VA and with the presence of MW. Both splitting tensile strength and flexural strength of volcanic concrete with and without VA or MW behaved similar to that of the corresponding compressive strength.

Water Miscibility, Surface Tension, Density, and Dynamic Viscosity of Hydrophobic Deep Eutectic Solvents Composed of Capric Acid, Menthol, and Thymol

Deep eutectic solvents (DESs) are rapidly emerging as environmentally benign and viable alternatives not only to common organic solvents but to relatively toxic ionic liquids as well. By judicious selection of the constituents and subsequent variation in their composition, the key physicochemical properties of the DESs can be easily tailored for a specific application. Impact of variation in constituents as well as their composition on important physical properties of natural DESs (NADESs) prepared using a common fatty acid n-decanoic acid (DA) and two naturally occurring monoterpenoids, thymol (Thy) and L(−)-menthol (Men), is assessed. Specifically, water miscibility, surface tension, density, and dynamic viscosity of 17 different DESs of three combinations of constituents, Men:DA, Thy:DA, and Thy:Men in four, four, and nine compositions, respectively, are measured. The water intake by the DESs under ambient conditions varies from 0.6 to 2.7 mol·kg–1 offering a means to gauge their hydrophobicity. Water miscibility is relatively lower for Men:DA DESs and higher for Thy:DA DESs. Surface tension values are within 28.37 mN·m–1 to 31.14 mN·m–1 under ambient conditions; they are higher for the DESs with the Thy constituent and vary systematically with DES composition. The densities of all the DESs are lower than that of water and decrease linearly with increasing temperature. While density does not vary with composition for Men:DA, it is found to increase linearly with an increase in Thy mole fraction for Thy:DA and Thy:Men DESs. The dynamic viscosity of the DESs are relatively lower as compared to the common tetralkylammonium salt- and metal salt-based DESs, and exhibit strong constituent and composition dependence. Rather than the Arrhenius-type expression, the temperature-dependence of the dynamic viscosity better conforms to the Vogel–Fulcher–Tammann (VFT) model with activation energy of the viscous flow varying systematically with the constituent and composition. Reported physical properties and their dependence on constituents/composition of the NADESs will enhance their utility and help establish them as novel alternate media in science and technology.

A Molecular View of the Surface Pressure/Area Per Lipid Isotherms Assessed by FTIR/ATR Spectroscopy

The macroscopic behavior of a lipid monolayer in terms of packing and compressibility properties is classically obtained from surface pressure/area per molecule isotherms. Molecular interpretations trying to fit the II/A curves have been attempted by molecular dynamics. In this regard, the simulation is performed by introducing parameters accounting for the lipid-lipid interaction in the monolayer plane. However, water, as an essential component of the interfacial phenomena, is not explicitly included in terms of molecular arrays. This drawback appears to be a consequence of the lack of experimental evidence that may complement the macroscopic view with the microscopic features. In this work, we propose that II/A curves can be reproduced from microscopic molecular data obtained with FTIR/ATR spectroscopy. The changes in surface pressure, in fact, changes in the surface tension of the lipid–water interphase, can be related to the acyl regions exposed to water and evaluated by the ratio of isolated-to-connected CH2 populations. In turn, the area changes correspond to the variations in the primary and secondary hydration shells of the phosphate region. The isolated/connected CH2 ratio represents the extension of the non-polar region exposed to water and is linked to the resulting water surface tension. The area per lipid is determined by the excluded volume of the hydration shells around the phosphate groups in correlation to the carbonyl groups. The derivative of the frequencies of the -CH2 groups with respect to the water content gives an insight into the influence of water arrangements on the compressibility properties, which is important in understanding biologically relevant phenomena, such as osmotic stress in cells and the mechanical response of monolayers. It is concluded that the water population distributed around the different groups dominates, to a great extent, the physical properties of the lipid membranes.

Extraction, characterization, and biosurfactant properties of extracellular polymeric substance from textile wastewater activated sludge

Textile wastewater treatment generates sludge that needs to be disposed of safely. The cost of sludge management is 50% of the total treatment cost of the wastewater. To reduce the expense, the sludge can be repurposed as a valuable resource by extracting extracellular polymeric substance (EPS). EPS contains polysaccharides, proteins, and humic substances, which are surface-active substances that act as potential biosurfactants. In this study, we investigated sludges (sludge 1 and sludge 2) from two different textile industries for EPS production. The results showed a maximum EPS yield of 179mg/g-activated sludge from the wastewater from sludge 2. The EPS from textile wastewater activated sludge had a protein/carbohydrate ratio of 0.27-0.56, lower than that of municipal activated sludge. This difference is due to variations in nitrogen/carbon ratio in these wastewaters. Based on the biosurfactant activity test, EPS from both textile wastewaters could lower the water surface tension to around 60mN/m and emulsify olive oil better than Tween 20 and 80. However, only EPS from sludge 2 showed better xylene emulsification than EPS from sludge 1 due to the difference in humic acid content.

Application of residual cooking oil to improve the production of a low-toxic biosurfactants extract

Residual cooking oil (RCO) bioconversion into value-added products is one of the best options to manage this waste. Thus, the feasibility of producing lipopeptides by Pseudomonas syringae pv tabaci using this residue is reported for the first time. Surface activity, stability, and cytotoxicity of biosurfactants were explored by surface tension, emulsification indexes (EI24), and mammalian cell viability assays. It was demonstrated that a mixture of RCO and glycerol (1:1) as carbon source increased the production titer from 1.47 to 2.70 g/L, syringopeptin being the main component. The produced lipopeptides were able to reduce the water surface tension down to38 mN/m and emulsify effectively (EI up to 67 %) a wide variety of hydrophobic compounds at 0.10 g/L. Moreover, these lipopeptides at 1.0 g/L resulted to be highly compatible with mammalian cells (viability superior to 70 %), demonstrating that at the working concentrations are non-toxic and thus, adequate for food and pharmaceutical applications.

Understanding the magnetizing process of water and its effects on cementitious materials: A critical review

Magnetized Water (MW) is a fascinating research subject for improving the properties of the cementitious composite due to its physicochemical alterations in cluster size and surface tension of water. However, these physicochemical changes have shown contradictory results in the literature. This paper intends to expound on physicochemical properties variations of MW and its effect on cement composite performance. Consequently, all existing Magnetic fields (MFs) for water treatment were classified into two main categories. The effective MF parameters of these methods on MW characterizations were discovered and collected from the literature, and they are proposed to be considered in future studies to make results more comparable and compatible. The different techniques for molecular cluster examination are introduced to understand each technique's solidity in water cluster investigations. Then the influence of MF on cluster size and surface tension of water was scrutinized, and the results of studies were summarized end of each section inside comprehensive tables. In the continuation, the charming effects of treated water with effective MF parameters on cement composites' fresh and hardened state were addressed to appreciate the magnitude to which MW affects cement composites properties.

Structural and physicochemical characterization of a rhamnolipid biosurfactant

Rhamnolipids are an important class of biosurfactants having many uses in pharmaceutical, agricultural, food, cosmetics, and detergent industries. The present study used various analytical techniques to characterize the biosurfactant produced by Achromobacter xylosoxidans PSA5. The characteristic absorption bands in FT-IR spectroscopy also revealed its glycolipid nature. NMR spectroscopy, in conjunction with the LC-MS analysis, identified the chemical structure of the biosurfactant as a di-rhamnolipid. The surface tension of water was lowered to 25.19 mN/m, and the rhamnolipid showed a critical micelle concentration of 174.375 mg/L. The highest emulsification index of 69.69% was observed against engine oil. Further, the activity of the biosurfactant was stable across a broad pH range (2-10), temperature (30-100°C), and salt concentrations (2, 4, 6, 8, and 10%). The surface-active properties and the stability of these biomolecules suggest their potential use in bioremediation, and the petroleum industry, particularly in extreme conditions.

Multiplexed electrospraying of water in cone-jet mode using a UV-embossed pyramidal micronozzle film

The electrospraying of water in the cone-jet mode is difficult in practical applications owing to its low throughput and the electrical discharge caused by the high surface tension of water. A film with multiple dielectric micronozzles is essential for multiplexed electrospraying of water in cone-jet mode without electrical discharge. Thus, a pyramidal micronozzle film with five nozzles was fabricated using the UV-embossing process. The pyramidal micronozzle film consisted of pyramidal micronozzles, a micropillar array, and an in-plane extractor, which were proposed to minimize wetting and concentrate the electric field to the water meniscus at the tip of the pyramidal micronozzle. The electrospraying of water using a single pyramidal micronozzle was visualized by a high-speed camera at a flow rate of 0.15–0.50 ml/h with voltages of 0.0–2.3 kV, −1.6 kV, and −4.0 kV at the water, guide ring, and collector, respectively. Three distinct modes, the dripping, spindle, and cone-jet modes, were observed and distinguished according to the motion of the water meniscus at the nozzle tip. The steady Taylor cone and jet were observed in a voltage range of 1.3–2.0 kV in water, particularly in cone-jet mode. Multiplexed electrospraying of water in cone-jet mode at a flow rate of 1.5 ml/h was performed using a pyramidal micronozzle film, demonstrating the potential for a high-throughput electrospraying system.

Effects of Magnetic Field on the Performance of Solar Distillers: A Review Study

Due to the rising demand for treated water, the enhancement of potable water yield technologies, such as traditional solar distillers, is a pressing concern. Solar desalination is one of the easiest techniques for producing fresh water from salt water. It has several benefits, not the least. It utilizes free solar energy. Moreover, it is a simple and inexpensive technique compared to other alternatives. They are, nevertheless, relatively inefficient devices. Many studies have been done to boost the daily output of solar stills by using many active strategies to produce a large amount of evaporation and condensation compared to a basic standard type distiller. The magnetic field (MF) is one of the most important and recent techniques affecting the productivity of the solar still due to its positive impact on the water evaporation rate. The primary focus of the current study is to review the effects of magnetic field approaches on the distillate production, performance, and thermal efficiency of several types of solar distillers. Based on previous studies, the magnetic field is responsible for increasing the partial pressure difference between water and glass cover. The change occurs in the hydration shells of the saltwater, which should enhance the evaporation rate and improve the performance of solar still. Besides, the magnetic field significantly reduces the surface tension of salty water, which leads to increased evaporation. Furthermore, the intensity, direction, position, and magnet sizes of magnetic have a strong effect on the rate of water evaporation as well as the rate of heat transfer.

Production of an ultrasound-assisted biosurfactant postbiotic from agro-industrial wastes and its activity against Newcastle virus.

The objective of this study is to optimize the biosurfactant production by Lactobacillus plantarum ATCC 8014 using low-cost substrates from industrial sources applying ultrasonication at 28 kHz frequency (power of 100 W). Given this, whey permeate and sugar cane molasses were screened to continue optimization using a central composite design to improve the production. Then, the effect of ultrasound was examined at different stages of microbial growth. The combination of whey permeate and sugar cane molasses with yeast extract (2.4 g/L) and inoculum size of 4.8% for 26 h of fermentation time significantly influenced biosurfactant production by reducing the surface tension of water (41.86 ± 0.24 mN/m). Moreover, ultrasonication led to the further reduction in surface tension value (39.95 ± 0.35 mN/m). Further, no significant differences were observed between products from synthetic and waste-based media. The biosurfactants exhibited antiviral activity against Newcastle disease virus (NDV) LaSota strain. It was discovered that biosurfactant produced in agro-food wastes with a significant antiviral effectiveness could be used to develop commercial application instead of chemical surfactants and biosurfactants from expensive synthetic media.

Preparation of porous Y2SiO5 ceramics with high porosity and extremely low thermal conductivity for radome applications

It is well known that aqueous gel-casting is challenging to prepare high-porosity ceramics due to the considerable drying shrinkage, cracking, and deformation of green bodies during drying caused by the high surface tension of water. Porous Y2SiO5 ceramics with high porosity were prepared by introducing carbon fibers as a support material in the drying process of aqueous gel-casting to reduce shrinkage during drying. Burning out the carbon fibers after drying does not negatively affect the properties of the porous ceramic. As prepared green bodies by aqueous gel-casting have low shrinkages of 8.69%–6.81% during drying processes and high compressive strength of 13.73 ± 1.55–10.66∼0.49 MPa. The higher compressive strength of the green body has a positive significance for processing porous ceramics into special-shaped structures. As prepared porous Y2SiO5 ceramics have high porosity of 73.94%–87.71%, lightweights of 1.16–0.55 g•cm3, extremely low thermal conductivities of 0.134 ± 0.006 to 0.051 ± 0.001 W•m−1•k−1, relatively low dielectric constants of 2.34–1.58, and tan δ are lower than 1.25 × 10−3. Porous Y2SiO5 ceramics with excellent dielectric properties and thermal insulation properties meet the requirements of thermal insulation and wave transmission integration of radome materials. Aqueous gel-casting also enriches the preparation methods of high-porosity Y2SiO5 ceramics.

Isolation and Partial Characterization of Glycolipopeptide Biosurfactant Derived from A Novel Lactiplantibacillus plantarum Lbp_WAM

Biosurfactants are amphipathic molecules generated by a variety of microorganisms with different biological functions. In this study, lactic acid bacteria were screened for their emulsification properties. However, the Lactiplantibacillus plantarum strain LBpWAM was molecularly identified using 16S rRNA, and its ability to produce surface-active peptides was investigated. The biosurfactant derived from L. plantarum LBp_WAM was shown to have the potential to reduce water surface tension from 72 mN.m-1 to 32 mN/m within a critical micelle concentration (CMC) of 2.4 mg.ml-1. The emulsification index (E24) values were evaluated for sunflower oil (60 ± 3.0%), glycerol (53.9 ± 0.11 %), olive oil (49.0 ± 2.0 %), mineral oil (50.7 ± 0.60 %), hexane (36.03±0.05 %), and kerosene (31 ±0.05 %). The biosurfactant was purified using gel filtration chromatography (GFC), and the molecular weight was determined using the SDS-PAGE method, indicating an approximate molecular weight of 19 kDa. Thin-layer chromatography (TLC) and Fourier transform infrared spectroscopy (FT-IR) were used to determine the molecular structure of the obtained molecule, which was found to be composed of protein, lipid, and polysaccharides. The biosurfactant's antibacterial activity was also examined, as it showed inhibitory effects against different species of Gram-positive and Gram-negative bacteria.