Study on Charge Oscillation-Induced Low-Frequency Electric Field
Electric field induced by charge oscillation has been investigated by simulation of the electric field distribution using the finite-difference frequency-domain method. In addition, the electric field was induced by spatial oscillation of a sample to which a DC voltage was applied. The simulation and evaluation of the electric field verified that the efficiency for inducing the electric field has a proportional relationship with the amplitude displacement of a charged object, and detecting the electric field from the top to the side of the object is possible. Keywords—static electricity; charge oscillation; electric field; low frequency
New technique for electrostatic charge measurement in gas–solid fluidized beds
Abstract Electrostatic charge generation within gas–solid fluidized bed reactors has been a concern to industry for many years. Over the years, numerous methods for measuring this phenomenon within a fluidization column have been proposed. This paper focuses on the design of a new method that minimizes effects such as extra charging due to particle handling and bed hydrodynamic disruption due to the location of the measurement device. In addition, the new method provides the bulk charge of the bed particles rather than a local measurement. The device is flexible and can be adapted to a range of fluidization columns. The new method developed consisted of a Faraday cup placed within the windbox of a fluidization column. The distributor plate was designed in such a way that it can be automatically opened to drop the charged fluidizing particles into the Faraday cup below. The new measurement technique was validated by conducting fluidization experiments in a system consisting of a 0.10 m in diameter carbon steel column with glass beads as the fluidizing particles. The technique was proven to be suitable for measuring the total net electrostatic charges in gas–solid fluidized beds.
Experimental energy barriers to anions transporting through nanofiltration membranes.
Environmentally relevant contaminants fluoride, chloride, nitrate, and nitrite face Arrhenius energy barriers during transport through nanofiltration (NF) membranes. The energy barriers were quantified using crossflow filtration experiments and were in the range of 7-17 kcal·mol(-1), according to ion type and membrane type (Filmtec NF90 and NF270). Fluoride faced a comparatively high energy barrier for both membranes. This can be explained by the strong hydration energy of fluoride rather than other ion properties such as bare ion radius, fully hydrated radius, Stokes radius, diffusion coefficient, or ion charge. The energy barrier for fluoride decreased with pressure, indicating an impact of directional force on energy barriers. The influence of temperature-induced pore radius variability and viscosity on energy barriers was considered. The novel link between energy barriers and ion properties emphasizes the importance of ion hydration and/or partial dehydration mechanisms in determining transport in NF.