This contribution aims to appraise, analyze and evaluate the literature relating to the interaction of electromagnetic fields (EMF) with matter and the resulting thermal effects. This relates to the wanted thermal effects via the application of fields as well as those uninvited resulting from exposure to the field. In the paper, the most popular EMF heating technologies are analyzed. This involves on the one hand high frequency induction heating (HFIH) and on the other hand microwave heating (MWH), including microwave ovens and hyperthermia medical treatment. Then, the problem of EMF exposure is examined and the resulting biological thermal effects are illuminated. Thus, the two most common cases of wireless EMF devices, namely digital communication tools and inductive power transfer appliances are analyzed and evaluated. The last part of the paper concerns the determination of the different thermal effects, which are studied and discussed, by considering the governing EMF and heat transfer (or bio heat) equations and their solution methodologies.
The study is devoted to the problem of processing the organic waste that is generated as a result of paper, textiles and other industries production as well as food waste. The growth of economic activity in Kazakhstan has resulted in a significant challenge with regard to industrial waste management. The accumulation of waste on the territory of the country has reached 31.72 billion tonnes, comprising approximately 2.5 billion tonnes of hazardous waste, 50 million tonnes of phosphorus-containing waste, over 2.5 million tonnes of lead-zinc waste and more than 120 million tonnes of solid domestic waste. The study object was the Shymkent-Kokys polygons. According to the research carried out, it was determined that the titer of microorganisms of the studied groups is 1–10 CFU/g in the soils selected around the garbage in the area of the Shymkent landfill. The titer of microorganisms in the soil horizons was high at a depth of 20–30 cm and the titer were 109 cells/mL. The structure of the soil microbiome obtained around the Shymkent Waste Landfill consists of actinomycetes, micromycetes, heterotrophic bacteria, nitrifying, nitrogen-fixing bacteria, enterobacteria, as well as algae and protozoa. It was found that strains KPA1, KPA2 Pseudomonas sp. strains KPA3, KPA4, KPA5 Bacillus sp. isolated from the soils of the Shymkent-Kokys landfill are able to recycle domestic waste with a high content of cellulose and organic substances up to 95%–97%. The findings can be used to develop more effective organic cellulosic waste management strategies and improve the environmental sustainability of various industries.
Disease epidemics may spread quickly and easily throughout nations and continents in our current global environment, having a devastating effect on public health and the world economy. There are over 513 million people worldwide who have been infected, and more than 6.2 million have died due to SARS-CoV-2. There are treatments but no cures for most viruses. Nevertheless, the spread of viruses can be limited by introducing antiviral coatings on public area surfaces and personal protective equipment (e.g., face masks). This work aims to fabricate a polymer-based coating with acrylic resin as a binder that possesses great antiviral activity against the Feline coronavirus (FCov). The chosen polymer, polyethylene glycol (PEG), is used as an antiviral agent because it contains “green” chemistry benefits such as non-toxicity, being inexpensive, readily recyclable, safe, natural, non-flammable, biocompatible, and biodegradable. The PEG/acrylic coating systems of different weight percentages were coated on the glass substrates by the spray-coating method and cured at room temperature for 24 hours. The developed PEG/acrylic coating system that contains 20 wt% of PEG exhibits the highest anti-viral activities (99.9% against FCov) compared to the other weight percentages. From this study, it has been observed that the hydrophilicity of the coating plays an important role in its antiviral activity. The developed coating has a hydrophilic property, in which the contact angle was measured at 83.28 ± 0.5°. The FTIR reveals that there are no existing toxic components or new components contained in the coating samples.
In order to explore the influence of the ferroelectric surface on the structure and properties of semiconductor oxides, the growth of CdS nanocrystals was regulated and controlled by taking single-crystal perovskite PbTiO3 nanosheets as the substrate through a simple hydrothermal method. Through composition design, a series of PbTiO3-CdS nanocomposite materials with different loading concentrations were prepared, and their microstructure and photocatalytic properties were systematically analyzed. Studies show that in the prepared product, CdS nanoparticles selectively grow on the surfaces of PbTiO3 nanosheets, and their morphology is affected by the exposed surfaces of PbTiO3 nanosheets. There is a clear interface between the PbTiO3 substrate and CdS nanoparticles. The concentration of the initial reactant and the time of hydrothermal reaction also significantly affect the crystal morphology of CdS. Photocatalysis studies have shown that the prepared PbTiO3-CdS nanocomposite material has a significant degradation effect on 10 mg/L of Rhodamine B aqueous solution. The degradation efficiency rises with the increase of CdS loading concentration. When degrading 10 mg/L Rhodamine B aqueous solution, the PbTiO3-CdS sample with a mass fraction of 3% can reach a degradation rate of 72% within 120 min.
This work investigates epoxy composites reinforced by randomly oriented, short glass fibres and silica microparticles. A full-factorial experiment evaluates the effects of glass fibre mass fraction (15 wt% and 20 wt%) and length (5 mm and 10 mm), and the mass fraction of silica microparticles (5 wt% and 10 wt%) on the apparent density and porosity, as well as the compressive and tensile strength and modulus of the hybrid composites. Hybrid epoxy composites present significantly higher tensile strength (9%) and modulus (57%), as well as compressive strength (up to 15%) relative to pure epoxy.
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