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Fluid Mechanics
Published in Michael A. Crabtree, The Concise Industrial Flow Measurement Handbook, 2019
And in turn, the dyne (Figure 2.16) is defined as: the force required to accelerate a mass of one gram at a rate of one centimetre per second per second: 1 dyne is equal to 10 μN (micro-newton)
Multiphase Flow in Porous Media
Published in Efstathios E. Michaelides, Clayton T. Crowe, John D. Schwarzkopf, Multiphase Flow Handbook, 2016
John R. Fanchi, John P. Seidle
Multiphase fluid flow in porous media depends on the interaction of the solid material with fluids in the pore space. The focus of this section is on the representation of rockfluid interactions using physical parameters such as relative permeability and capillary pressure. 11.5.1 Surface Tension and Interfacial Tension e pressure di erence across the interface between two immiscible uids results in a normal force. e unbalanced force leads to a tension at the interface that is balanced by a force due to the pressure di erence when the surface of the interface is curved. e tension between liquids at a liquidliquid interface is called interfacial tension (IFT), and the tension at a gasliquid interface is called surface tension. Surface tension may be considered a force per unit length in a surface (dyn/cm, or equivalently, mN/m) or a free energy per unit surface area (erg/cm2, or equivalently, mJ/m2).
Flow of Incompressible Fluids
Published in Raymond Mulley, Flow of Industrial Fluids—Theory and Equations, 2004
By far, the most popular unit of viscosity remains the poise or, more exactly, one derived from it, the centipoise. In other words, none of the above. The poise is based upon the older cgs (centimeter-gram-second) system. The unit of force in this system was the dyne. The dyne was a derived unit that in turn had units of gm⋅cm/s2. When viscosity is given in poises, its units are, () μp=FZAV=gm⋅cms2cm⋅scm2⋅cm=gmcm⋅s
Luminescence and thermoluminescence of Er3+-doped CaF2 nanomaterials
Published in Radiation Effects and Defects in Solids, 2023
Vu Thi Thai Ha, Thi Anh Thu Do, Trong Thanh Nguyen, Thi Dieu Thuy Ung
CaF2 and NH4F are soluble in water, but in this medium it is difficult to control the chemical reaction rate and the growth of NPs. High concentrations of Ca2+ and F– ions result in a fast reaction and lead to the formation of NPs with large sizes (150–250 nm). It is worth noting that a mixture of water and ethanol at a volume ratio of 1:1 provides smaller nanoparticles. It could be due to the surface tension of ethanol (22.30 dyne/cm at 20°C) being much lower than that of water (72.75 dyne/cm at 20°C), which reduces the attractive force between the colloidal particles. In the synthesis by the precipitation method, the pH value of the solution plays an important role. In our case, the pH value from 5 to 6 gives the highest reaction yield. In addition, NaOH solution should not be used to keep pH 5–6 to avoid the formation of NaF leading to a reduction in reaction efficiency.
Absorbency of synthetic urine by cotton nonwoven fabric
Published in The Journal of The Textile Institute, 2021
Rupali Dhiman, R. Chattopadhyay
The measurement of pore sizes by Porolux 100 is based on gas-liquid displacement principle. A sample (approximately 2.5 cm in diameter) was completely immersed in the porofil (surface tension of 16.0 dyne/cm) wetting liquid for 30 s. The sample was placed in the sample holder and the pressure was raised gradually so that the liquid is forced to move out from the larger pores initially, followed by the smaller pores of the wetted sample. Per cent flow versus diameter and air-flow versus air pressure graphs were obtained. The method was used to measure the bubble point, smallest pore (SP) diameter, mean flow pore (MFP), cumulative filter flow, and pore size distribution etc. MFP was calculated at a point where the wet curve and half of the dry curve converged. The maximum and minimum pore diameters were determined by the bubble point and from the pressure at which wet and dry curves converged, respectively. A bubble point is a pressure at which the first flow of gas across the wet membrane is observed.
Oil-in-gold nanoparticle solution emulsion stabilized with amphiphilic polymers and its stability under NIR irradiation
Published in Journal of Dispersion Science and Technology, 2018
Figure 4 shows the air/water interfacial tension of P(HEA/PMA) solutions. The interfacial tension decreased rapidly when the concentration increased to 0.05 mg/mL and thereafter it reached a plateau. The interfacial tension at a given concentration was lower in the order of P(HEA/PMA)(90/10) solution < P(HEA/PMA)(93/7) solution < P(HEA/PMA)(95/5) solution < P(HEA/PMA)(97/3) solution < P(HEA/PMA)(100/0) solution. For example, the minimum surface tension of P(HEA/PMA)(90/10) solution, P(HEA/PMA)(93/7) solution, P(HEA/PMA)(95/5) solution, P(HEA/PMA)(97/3) solution, and P(HEA/PMA)(100/0) solution was 44.6 dyne/cm, 47.7 dyne/cm, 50.9 dyne/cm, 54.5 dyne/cm, and 62.3 dyne/cm, respectively. That is, the interfacial activity was higher as the PMA content was higher. HEA is a hydrophilic monomer and PMA is a hydrophobic monomer. If HEA is copolymerized with PMA, the copolymer would be amphiphilic. As the HEA content increases to a certain degree, the amphiphilicity would increase, resulting in an increased interfacial activity.