Window with Electrostatic Protection against Dust, Smoke, and Viruses

The article analyzes the effect of dangerous aerosols on the human body. In order to purify the air from aerosols, the effect of an electric field on them is considered. The electric and dielectrophoretic forces acting on submicron particles in an inhomogeneous electric field of two parallel wires are calculated. It is shown that part of this field is identical to the field between the wire and the grounded plate electrode located in the middle between the wires. This allows using a known formula for the electric field of a two-wire line to calculate the field gradient and the effect of dielectrophoresis on neutral particles. Smoke and dust particles already carry a negative charge, and a more or less uniform electric field is enough to move them. To filter neutral water droplets infected with the virus, you need either a field with a large gradient or a corona discharge. The paper shows that the polarization of particles in an electric field causes the particles to stick together, and larger particles settle faster on the electrodes of the filter. The design of a transparent electrostatic precipitator is proposed, which can be used to protect indoor air from external smoke, dust, or viruses.

Development of a Mesoporous Silica-Supported Layered Double Hydroxide Catalyst for the Reduction of Oxygenated Compounds in E. grandis Fast Pyrolysis Oils

Biomass fast pyrolysis oil is a potential renewable alternative to fossil fuels, but its viability is constrained by its corrosiveness, low higher heating value and instability, caused by high oxygenate concentrations. A few studies have outlined layered double hydroxides (LDHs) as possible catalysts for the improvement of biomass pyrolysis oil characteristics. In this study, the goal was to reduce the concentration of oxygen-rich compounds in E. grandis fast pyrolysis oils using CaAl- and MgAl- LDHs. The LDHs were supported by mesoporous silica, synthesised at different pHs to obtain different pore sizes (3.3 to 4.8 nm) and surface areas (up to 600 m2/g). The effects of the support pore sizes and use of LDHs were investigated. GC/MS results revealed that MgAl-LDH significantly reduced the concentrations of ketones and oxygenated aromatics in the electrostatic precipitator oils and increased the concentration of aliphatics. CaAl-LDH had the opposite effect. There was little effect on the oxygenate concentrations of the heat exchanger oils, suggesting that there was a greater extent of conversion of the lighter oil compounds. Bomb calorimetry also showed a marked increase in higher heating values (16.2 to 22.5 MJ/kg) in the electrostatic precipitator oils when using MgAl-LDH. It was also found that the mesoporous silica support synthesised at a pH of 7 was the most effective, likely due to the intermediate average pore width (4 nm).

Laser synthesis of a weakly agglomerated aluminium oxide nanopowder doped with terbium and ytterbium

This paper describes a method of femtosecond laser synthesis of nanoparticles of powdered aluminum oxide doped with terbium and ytterbium was developed. The formation of a plasma torch of nanoparticles of a powdery material is carried out as a result of ablation under the influence of a sharply focused beam of femtosecond laser radiation with an intensity of 108- 1010W/m2. The radiation source is the TETA-10 laser system. SEM images of the obtained nanopowders are presented. Spherical nanoparticles of narrow particle size distribution in the range from 5 to 15 nm was synthesized with the ability to control the size of nanoparticles by purposefully changing the parameters and characteristics of pulsed radiation in the treatment area. The design of a specialized high-voltage electrostatic precipitator up to 25 kV for capturing ablated nanoparticles in an electron cloud of increased concentration was developed.