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Bioremediation of Petroleum Hydrocarbons (PHC) using Biosurfactants
Published in R.Z. Sayyed, Microbial Surfactants, 2022
Veeranna Channashettar, Shaili Srivastava, Banwari Lal, Anoop Singh, Dheeraj Rathore
Surface tension is the most important property of tensioactive agents and is the attractive force between the molecules in liquids (Pacwa-Plociniczak et al. 2011). Biosurfactants help in decreasing surface tension and the interfacial pressure. The tension between the air/water and oil/water phases are respectively known as the surface tension and interfacial tension (Banat et al. 2010). A tensiometer is used for the quantitative measurement of the surface tension of liquids. Surface tension is the basis of most initial evaluations for the identification of the presence of a surfactant in the medium. The air/water surface tension for distilled water is about 72 mN/m (or dynes/cm). The solubility limit of surfactants is described by the critical micelle concentration (CMC) and CMC of biosurfactants ranges from 1 to 2000 mg/L, whereas interfacial (oil/water) and surface tensions are respectively approximately 1 and 25-30 mN/m. Biosurfactant, surfactin produced by Bacillus subtilis reduces the surface tension of water to 25 mN m−1 and interfacial strain for water/hexadecane to under 1 mN m−1 (Cavalero and Cooper 2003). Pseudomonas aeruginosa produces rhamnolipids which reduced the surface tension of water to 26 mN m−1 and interfacial strain of water/hexadecane to under 1 mN m−1 (Chakrabarti 2012).
Tensiometer-Based Irrigation Scheduling: Drip-Irrigated Bell Pepper Under Naturally Ventilated Polyhouse
Published in Ajai Singh, Megh R. Goyal, Micro Irrigation Engineering for Horticultural Crops, 2017
Ashwani Kumar Madile, P. K. Singh
Tensiometers are delicate instruments that must be handled, installed, and maintained correctly. By using the information from tensiometers, one can become more knowledgeable about the water-holding characteristics of the soil and the water needs of the plants. Tensiometers can help us to avoid plant drought stress and meet plant water needs without wasting irrigation water supplies [30].
Experimental study on effects of surfactant and spray inclination on heat transfer performance in nonboiling regime
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Sukhdeep Singh, Rajeev Kukreja
The effect of three distinct surfactants on heat transfer performance at various concentrations have been studied. All surfactant systems were characterized before the experiments by measuring physical characteristics such as surface tension, viscosity, and contact angle shown in Figures 5 and 6. A surface tensiometer was used to measure the surface tension of the working fluid. The ability of a liquid to wet a solid surface is determined by its surface tension. The contact angle of the test samples was measured using apex contact angle measurement equipment. To reduce the possibility of human error in contact angle measurement, the sample surface is cleaned with acetone and dried for a few minutes before being measured. A viscometer was used to measure the viscosity of all of the working fluids.
Processing of hardened steel by MQL technique using nano cutting fluids
Published in Materials and Manufacturing Processes, 2021
Anshuman Das, Saroj Kumar Patel, Manoranjan Arakha, Abhijit Dey, Bibhuti Bhushan Biswal
The surface tension of the fluid has been measured using a tensiometer, Force Tensiometer – K100 (KRUSS). It is widely considered the simplest and most accurate method for surface tension measurement. The principal measuring methods used by the K100 are based on the precise measurement of the force which occurs when wetting a measuring probe or a solid sample. A special force sensor is used with a particularly high resolution for the instrument in order to obtain reliable, accurate measurements, for example for determining surface and interfacial tension. To ensure accurate measuring results, measuring probes are used such as rings and plates with highly accurate contours. These ensure an exact correlation between measured force and the surface or interfacial tension. The software-controllable sample stage moves in a wide speed range and communicates its exact position to the software with a resolution of 0.1 μm.
Foaming in aqueous solutions of zwitterionic surfactant in presence of monovalent salts: The specific ion effect
Published in Chemical Engineering Communications, 2020
Shailesh R. Varade, Pallab Ghosh
Surface tension of the aqueous solutions of DDAPS was measured at different concentrations varying from 0.1 to 2.8 mol m−3 in the presence of CsCl, NaCl, and LiCl. A digital tensiometer [make: Krüss (Hamburg, Germany), model: K9] was used for the surface and interfacial tension measurements. A Wilhelmy plate and a du Noüy ring made of an alloy of platinum and iridium were employed for measuring the surface and interfacial tensions, respectively. The experimental procedures followed the ASTM Standards D1331–14 (2014) and D1331–11 (2014), respectively. The sample vessels, the plate, and the ring were cleaned before each analysis. The plate and the ring were burnt on a Bunsen burner till they reached the red-hot condition. The intense burning was carried out so that the liquid and the sample adhering to the plate (or the ring) from the previous experiment were totally removed. For performing the surface tension measurement, the plate was dipped to an appropriate depth in the aqueous surfactant solution and was allowed to stand for 1 h. This provided the surfactant molecules sufficient time to reach equilibrium adsorption. Subsequently, the plate was slowly pulled out through the surface of the aqueous solution at a speed of ∼0.5 mm s−1. The value of surface tension displayed by the tensiometer was recorded. This procedure gave surface tension of very high accuracy and the data were easily reproducible.