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Membrane Technologies for Water Purification
Published in P.K. Tewari, Advanced Water Technologies, 2020
The layer of solution adjacent to the membrane surface becomes depleted in the permeating solute on the feed side of the membrane and enriched in this component on the permeate side. Equivalent concentration gradients are also formed for the other components of the feed solution. The concentration polarization reduces the concentration difference across the membrane, decreasing its flux and the membrane selectivity, which can significantly affect membrane performance.
VLSI Scaling and Fabrication
Published in Manoj Kumar Majumder, Vijay Rao Kumbhare, Aditya Japa, Brajesh Kumar Kaushik, Introduction to Microelectronics to Nanoelectronics, 2020
Manoj Kumar Majumder, Vijay Rao Kumbhare, Aditya Japa, Brajesh Kumar Kaushik
At the time of the oxidation process, the silicon is either heavily or moderately doped with P-type or N-type depending on the case. In order to understand, we first define the term segregation coefficient that is nothing but the ratio of an equivalent concentration of dopant in the silicon to the equivalent concentration of the dopant in silicon dioxide [27]. The redistribution process mainly depends on the ratio of solubility of Si and SiO2, where the redistribution of dopant will continue until the concentration at the interface becomes the same as the ratio of their solubility in both the materials [28]. The segregate coefficient can be denoted by k and expressed as equation (2.8). The k of different dopants in Si is summarized in Table 2.3. k=solubilityinSisolubilityinSiO2
Electrochemical Composition Measurement
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Michael J. Schöning, Arshak Poghossian, Olaf Glück, Marion Thust
For practical applications, there are two aspects to be dealt with: often a total ionic strength adjuster buffer (TISAB) is added to both the standard solutions and the test solution (same temperature) to achieve comparable ionic strengths. Then, the potential difference can be assigned to the equivalent concentration of the calibration curve. Various methods for calibration calculations are described by, for example, Gran’s plot or the standard addition method (Mendham et al. 2000). Because all measurements take place in dilute solutions (≤0.1 M), ion concentrations can be used in the Nernst equation instead of ion activities.
Synthesis of a lignin-based alcohol ether carboxylate surfactant and its application as cotton fiber detergent
Published in Journal of Dispersion Science and Technology, 2023
Juhua Ou, Zhenxing Kong, Rui Yang, Zilin Dai
Figure 5 shows the emulsifying ability of KLS and KLSU aqueous solution with different concentrations. By adding of KLS, the emulsifying ability of water increased as the concentration of samples increased. Compared with KLS samples, KLSU exhibited higher emulsifying ability. After ultrasound treatment, KLSU had a high emulsifying ability at equivalent concentration of aqueous solution. KLSU had lower cmc, the inter-molecular hydrogen bond and electric double layer structure take place due to the presence of more ether and ester bonds in KLSU solutions. The steric hindrance and electrostatic repulsive force of KLSU increased. Therefore, the interfacial film formed by adsorption at the interface is more tough and not easy to break, a higher emulsifying ability was obtained.[29]
Development of a novel particle mass spectrometer for online measurements of refractory sulfate aerosols
Published in Aerosol Science and Technology, 2021
Yuya Kobayashi, Yu Ide, Nobuyuki Takegawa
The limit of detection (LOD) for sulfate aerosols can be estimated as the equivalent concentration at three times the standard deviation (3σ) of the integrated ion signals for repeated ZA measurements (9–12 samples for each compound). The equivalent concentration is calculated as the ratio of the 3σ value to the product of the sensitivity at m/z 48 or 64 and sample air volume, as indicated by Equation (9). The time window for the ion signal integration was set at 0–30 s. The LOD values estimated by this method are listed in Table 2. The LOD values depended on the m/z peaks selected, probably because the background ion signals varied with m/z. Based on the estimated LODs, the current system could be used for measuring relatively high concentrations of sulfate in urban air, as shown in Figure 8, whereas the sensitivities at m/z 48 or 64 need to be improved by approximately one order of magnitude for measuring low concentrations of sulfate in remote areas.
Generalized Computer Model Calibration for Radiation Transport Simulation
Published in Technometrics, 2021
Michael Grosskopf, Derek Bingham, Marvin L. Adams, W. Daryl Hawkins, Delia Perez-Nunez
The impurity model (i.e., the computer model) to be calibrated takes advantage of the physical fact that the impurities most important for neutron transport, and likely to be present in graphite, all have neutron-absorption cross sections that are proportional to for low neutron energy (E). This means, for example, that a given concentration of one impurity element can be modeled as a different concentration of a different element. For example, each atom of boron-10 has the same effect on low-energy neutrons as 4.1 atoms of lithium-7. Our impurity model therefore groups all impurities into an “equivalent” concentration of boron. Calibration of the model means inferring the equivalent boron concentration of the actual impurities in the graphite.