This work presents a selective overview of natural fogs in terms of fog types, forms and states of occurrence, physical, micro-physical, chemical and dynamic properties, basic characterizing parameters, etc. In focus are related achievements and contributions reported mainly during the last decade and a half, as a result of both laboratory studies and field observations. Processes of homogeneous and heterogeneous nucleation are analyzed in the aspects of condensation, nuclei diversity and specifics, as related to the activation, growth and deposition of fog droplets. The effect is highlighted of the water vapor’s partial pressure on the surface tension of the liquid water–air interface and the freezing point of the water droplets. Some problems and aspects of fog modeling, parameterization, and forecasting are outlined and discussed on the examples of newly developed relevant 1D/3D theoretical models. Important issues of fog impacts on the air quality, ecosystems, water basins, societal life, and human health are also addressed and discussed, particularly in cases of anthropogenically modified (chemical, radioactive, etc.) fogs. In view of reducing the possible negative effects of fogs, conclusions are drawn concerning the new demands and challenges to fog characterization imposed by the changing natural and social environment and the needs for new data on and approaches to more adequate observations of fog-related events.

Mechanical properties of polymer membranes (strength, hardness and elasticity) are very important parameters for the application performance, e.g. water purification. We study the tensile and surface mechanical properties of hollow fiber and flat sheets mat membranes based on PES and PVDF polymers. Tensile test, nanoindentation and atom force microscopy are used for characterization at macro and nanoscale. Mechanical properties are correlated with pore structure of membranes. The reinforced PVDF HF hollow fiber membranes show 30-fold higher stiffness and 3-fold higher hardness compared to non-reinforced PES HF. Surface mechanical properties of flat sheet membranes are strongly improved by decreasing the pore size. The smoothest surface with 100–200 nm roughness has the best surface mechanical performance obtained by nanoindentation.

We constructed a new type of light-weight, nanocarbon based thin film material having good mechanical properties, thermal stability, and electromagnetic shielding efficiency. Our method, 3D printing combined with hot pressing, is a cheap and industrially upscalable process. First a sandwich structure was created by layer-to-layer deposition of alternating 100 μm thick nanocarbon containing plastic layers and 100 μm thick pristine plastic layers, repeated as building blocks. The 3D printed samples were hot pressed to obtain thin films of 10–30 μm thickness. We used a commercial nanocarbon 3D printing filament (Black Magic). TEM investigations revealed the nanocarbon filler to be a mixture of graphene sheets, short carbon nanotubes, fishbone nanotubes, graphitic nanoparticles, and carbon black. Small-angle X-ray scattering and X-ray diffraction studies showed some amorphization of the nanocarbon filler as a consequence of the hot pressing. The nanoindentation hardness, nanoscratch hardness, and Young's modulus increase gradually by increasing the number of layers in the films, due to an increase of the amount of nanocarbon filler. Microwave absorption also increases continuously with the number of nanocarbon layers, reaching 40% for 3 nanocarbon layers. We demonstrate that unlike most conventional composites loaded with nanocarbons having pronounced dielectric properties, when the real part of permittivity Re(ε) is much higher than its imaginary part Im(ε) at high frequencies, a combination of 3D printing and hot pressing allows the fabrication of composites with Re ε ≈ Im ε in a very broad frequency range (0.2–0.6 THz). Our new 3D printed—hot pressed thin films may compete with the CVD graphene sandwiches in electromagnetic shielding applications because of their easier processability and low cost.

Lab experiments related to artificial fog studies are limited due to instrument sensitivity to small fog and aerosol particles; therefore, the goal of this work is to evaluate aerosol solute effects on fog physical properties in a lab environment. To reach the goal, an automated fog-generating system was designed and that includes controlled chemical compounds dissolved in pure water. In the analysis, the impact of changing the mass concentration of potassium dihydrogen phosphate—KH₂PO₄, urea-CO(NH₂)₂, and potassium hexacyanoferrate trihydrate-K₃(Fe(CN)₆) on fog droplet size spectra is studied, because visibility is directly related to fog droplet spectra and aerosol composition. In the experiment, various microphysical conditions, including fog droplet size and volume concentration, were analyzed as a function of changing aerosol composition/spectra and fixed thermodynamic conditions. The results showed that fog droplet size spectra vary with the addition of chemical impurities to the pure water volume. For example, increasing KH₂PO₄ concentration compared to distilled water volume resulted in a higher mean particle size, which led to faster droplet settlement, and that resulted in cleaning air more efficiently compared to pure water fog. Overall, both issues and challenges of the experimental fog generating system with respect to water and aerosol solutions resembling CRBN (chemical, radiological, biological, and nuclear agents) characteristics are provided and evaluated.

Early identification of viruses leads to more efficient disease management and control, and is extremely important. A possible new approach for creating virus sensors is the Electromagnetic echo effect (EMEE). An important feature is that the signal from EMEE is highly dependent on the state of the irradiated body. This makes it possible to control ongoing reactions, even if these reactions are invisible to the human eye or other equipment. This article shows the possibility of registering reaction occurring in the presence of an avian coronavirus causing infectious bronchitis, strain Massachusetts. The same methodology can be applied for other types of viruses as well.