The Experts below are selected from a list of 12681 Experts worldwide ranked by ideXlab platform

Chingping Wong - One of the best experts on this subject based on the ideXlab platform.

  • a facile and clean process for exfoliating mos2 nanosheets assisted by a Surface Active Agent in aqueous solution
    Nanotechnology, 2018
    Co-Authors: Zhishu Guan, Chao Wang, Suibin Luo, Yingbang Yao, Rong Sun, Chingping Wong
    Abstract:

    A facile, efficient and environmentally friendly process to exfoliate MoS2 is essentially critical to apply the obtained mono- and few-layer nanosheets in various electronic devices and sensors. Here we report a liquid phase exfoliation method for exfoliation of MoS2, which employs a surfactant of sodium dodecyl benzene sulfonate (SDBS) in water. The nonpolar benzene rings in SDBS can firmly bind to the MoS2 layer, facilitating the effective exfoliation of nanosheets in aqueous solution. It is found that the exfoliation efficiency and thickness of MoS2 nanosheets are related to the concentration of SDBS, and the mechanism was investigated. Defect free mono- and few-layer MoS2 nanosheets are obtained by controlling the amount of SDBS in solution, which exhibit stable dispersion in water over months, and it renders them as having great potential for solution-based device fabrication.

Steven L Bryant - One of the best experts on this subject based on the ideXlab platform.

  • a pressure decay method to determine influence of a Surface Active Agent on interface and internal resistances to gas liquid mass transfer
    Chemical Engineering Journal, 2020
    Co-Authors: Zehao Yang, Ali Telmadarreie, Mingzhe Dong, Steven L Bryant
    Abstract:

    Abstract When gas dissolves into a liquid, interface resistance can limit the mass flux. Increasing or decreasing interface resistance by means of Surface-Active Agents is of interest in applications ranging from biomedicine to petroleum recovery. This paper describes a pressure-decay methodthat allows systematic investigation of both interface resistance and internal (diffusive) resistance during gas-to-liquid mass transfer; introduces a mathematical modeling approach that determines both resistances simultaneously; and provides experiments in which only the interface resistance varies. In the pressure decay method, the system pressure is recorded as gas transfers across the gas/liquid interface and diffuses within the liquid. It allows initiating the experiment at a prescribed pressure with high reproducibility, facilitating the interpretation of a series of experiments. The exact solution of the 1D resistance-in-series model is derived. An accurate approximation is further reported to analyze experiments conveniently. The interface resistance is systematically varied in a static nitrogen/water system by adding small concentrations of oleic acid. As the concentration of oleic acid increases, the mass transfer coefficient decreases or the interface resistance increases. The effect is significant: at a concentration of 2 ppm, at which concentration the interface resistance is almost four times greater than that for pure water. The oleic acid has little effect on the diffusion coefficient of nitrogen in water due to its low concentration. The model comparison indicates the range of Biot number when the interface resistance or internal resistance must be accounted for. The characteristic chart can effectively contribute to a qualitative analysis of the gas–liquid mass transfer process when the effect of Surface-Active Agents is considered.

Ruey-shin Juang - One of the best experts on this subject based on the ideXlab platform.

  • applications of a lipopeptide biosurfactant surfactin produced by microorganisms
    Biochemical Engineering Journal, 2015
    Co-Authors: Weichuan Chen, Ruey-shin Juang
    Abstract:

    Abstract Surfactin, one of the most powerful biosurfactants, is a lipopeptide-type biosurfactant that is generated by the gram-positive, endospore-producing, microorganism, Bacillus subtilis . The chemical structure of surfactin is composed of seven amino acids that are bonded to the carboxyl and hydroxy groups on long chain fatty acids (C 13 –C 15 ). The potential applications of surfactin are therapeutic applications, and environmental applications. However, the high cost of surfactin production and its low yields limit its range of commercial applications. This work therefore develops the natural production a Surface Active Agent by microorganisms and evaluates the microbial production system, the purification process, the identification process and the potential applications of surfactin.

Mateusz M Iwanski - One of the best experts on this subject based on the ideXlab platform.

  • synergistic effect of f t synthetic wax and Surface Active Agent content on the properties and foaming characteristics of bitumen 50 70
    Materials, 2021
    Co-Authors: Mateusz M Iwanski
    Abstract:

    The level of the properties of bituminous mixtures produced with water foamed bitumen relies on the optimum characteristics of the bitumen. One way to achieve the desired characteristics is to modify the bitumen with chemical additives before it is foamed. Bitumen 50/70 treated with a Surface-Active Agent (SAA) at 0.2%, 0.4% and 0.6% and Fischer-Tropsch (F-T) synthetic wax at 1.5%, 2.0%, 2.5% and 3.0% was used in the tests. The effect of the modifiers was investigated by assessing bitumen properties (penetration, softening point, Fraass breaking point and dynamic viscosity at 60 °C, 90 °C and 135 °C) and foam parameters (maximum expansion-ER, half-life-HL). For statistical evaluation of the test results, models of the properties of bitumen 50/70 were developed as a function of the contents of F-T synthetic wax and SAA. It was found that 2.0% F-T wax and 0.6% SAA were optimum contents for achieving the desired standard properties and foam characteristics of the tested binder. The developed models allow determining the composition of the modified binder depending on the required foam characteristics for specific applications in road construction. The recommended composition of the chemical additives used to modify the binder was also established to ensure its optimum properties.

Chao Wang - One of the best experts on this subject based on the ideXlab platform.

  • a facile and clean process for exfoliating mos2 nanosheets assisted by a Surface Active Agent in aqueous solution
    Nanotechnology, 2018
    Co-Authors: Zhishu Guan, Chao Wang, Suibin Luo, Yingbang Yao, Rong Sun, Chingping Wong
    Abstract:

    A facile, efficient and environmentally friendly process to exfoliate MoS2 is essentially critical to apply the obtained mono- and few-layer nanosheets in various electronic devices and sensors. Here we report a liquid phase exfoliation method for exfoliation of MoS2, which employs a surfactant of sodium dodecyl benzene sulfonate (SDBS) in water. The nonpolar benzene rings in SDBS can firmly bind to the MoS2 layer, facilitating the effective exfoliation of nanosheets in aqueous solution. It is found that the exfoliation efficiency and thickness of MoS2 nanosheets are related to the concentration of SDBS, and the mechanism was investigated. Defect free mono- and few-layer MoS2 nanosheets are obtained by controlling the amount of SDBS in solution, which exhibit stable dispersion in water over months, and it renders them as having great potential for solution-based device fabrication.

  • On-Demand Hydrogen Generator Based on the Reaction between Aluminum Slurry and Alkaline Solution
    Advanced Materials Research, 2011
    Co-Authors: Xiani Huang, Shu Liu, Chao Wang, Da Chen, Yuexiang Huang
    Abstract:

    In the present work, the aqueous slurry containing 30 wt% solid aluminum particles was prepared, using paraffin oil and oleic acid dispersant and Surface Active Agent respectively. The results showed that no obvious aluminum particle sediment was observed even after being kept it at room temperature in air up to 15 days. The hydrogen generator based on the reaction of the aluminum slurry and sodium hydroxide aqueous solution was manufactured and could supply a maximum hydrogen flow rate of 20 NL/min. The dew point of the hydrogen from the generator was lower than -40oC, indicating the high purity of the as-obtained hydrogen. As expected the X-ray diffraction patterns revealed that the byproduct was bayerite.