Surface texturing is one of the most effective approaches to modifying the surface to improve many properties: tribological, corrosion resistance, microhardness and others characteristics of a number of engineering materials. Among the surface texturing techniques developed in recent years, the most widely used method is the laser surface texturing method (LST) due to its high flexibility, superior texturing accuracy and good process controllability and reproducibility. With its rapid development, LST has attracted considerable attention in various industries such as automotive, biomedical and aerospace. The present study considers the changes in roughness in different modes of laser texturing of stainless steel specimens 304. The effects and role of individual laser parameters on the change in roughness are analyzed as a main characteristic of the surface properties of the processed material. Heating and its surface melting is one of the studied effects and its role in changing the roughness. The focus of the study is on the process of laser–material interaction as a function of absorbed energy density, pulse frequency, scan rate, and overlap coefficients leading to different effects of LST parameters. It has been found that increasing the energy density, accompanied by a decrease in the frequency and speed of scanning, can increase the surface roughness.

Depending on the processing of a particular material, the laser marking process must meet certain requirements. A certain laser peak intensity or fluency must be reached on the treatment surface above which the laser ablation process starts. Some experimental studies have shown that this particular marking threshold is related to many other parameters characterizing the laser source. This requires the realization of an appropriate combination of peak power or pulse energy and the radius of the beam in focus, the frequency of the laser pulses as well as the pulse duration. Achieving high resolution in the marking process requires optimal focusing, and this in turn is associated with the presence of high quality generated and propagated laser radiation. The study concerns the process of laser marking of CT80 carbon tool steel products with wide application in industry. Numerical experiments are performed with specialized software TEMPERATURFELD3D to obtain two-dimensional and three-dimensional temperature fields in the laser impact zone. The influence of the duration of the pulses of fibre laser on the process is investigated. Graphs of the dependence of normalized temperature on time and depth for pulse duration on 10 ns, 100 ns and 1 μ s are discussed.

In modern production, each finished product entering the market is identified by a special marking. Each mark must meet requirements such as good coding, easy to see, easy to read by certain readers, stable over time, etc. In the present casting, laser marking of the C75 steel was carried out with a fiber laser with an average power of P = 30 W and a wavelength of λ = 1064 nm. For semi-contrast marking, marking speeds from 100 mm/s to 700 mm/s, average power from 10 to 30 W, raster pitch from 20 µm to 60 µm, scanning frequency from 20 kHz to 150 kHz were investigated as constant parameters are the pulse duration τ =100 ns, number of repetitions N = 1 and defocus Δ f = 0 mm. The influence of the changing parameters on the contrast was established, and experimental dependences were constructed. The achieved research results show that to obtain a high contrast mark, the average power should be above 20 W, the scanning speed up to 300 mm/s, the scanning frequency up to 50 kHz and the raster pitch up to 40 µm.

As the world shifts towards more sustainable and eco-friendly practices, industrial hemp (Cannabis sativa L.) is gaining recognition as a versatile crop with numerous applications. The Baltic Sea region is well-suited for hemp cultivation, with its temperate climate and varied soil types. This study evaluates the suitability of various hemp varieties for the region, focusing on their ability to produce high-quality biomass, fibers, seeds, and dual-purpose products. The findings will contribute to the development of a thriving hemp industry in the region. Five years of research was conducted to investigate the productivity of 12 industrial hemp varieties, including 7 varieties mainly developed for seed production and 5 varieties mainly designed for fiber production. The results showed significant differences in yields among the varieties, with ‘Bialobrzeskie’ exhibiting the highest biomass yield (47.2 t ha⁻¹) and ‘Futura 75’ producing the highest fiber yield (10.8 t ha⁻¹). ‘Henola’ demonstrated the highest seed yield (3.5 t ha⁻¹), while ‘KA-2-2011’ and ‘USO-31’ were identified as dual-purpose varieties suitable for fiber (3.4 and 6.4 t ha⁻¹, respectively) and seed production (2.2 and 1.3 t ha⁻¹, respectively). The calorific value of hemp shives is comparable to wood fuels, indicating their potential as a viable fuel source. The results offer farmers a crucial tool for selecting the best-suited varieties for their specific region, promoting sustainable agriculture practices.

The report investigates the role of power density of melting and evaporation and speed to realize several laser technological processes on copper samples for a fibre laser and a CuBr laser. A methodology has been developed to determine preliminary operating intervals of power density for different speeds for the laser marking, laser ablation and laser texturing processes. From theoretical calculations, graphics of the dependences of the critical power density of melting and evaporation on the speed were drawn. Areas where oxidation, melting or evaporation occur were defined. Comparing the theoretical results and the obtained experimental results shows a very good convergence between them for both laser sources.

Silver has been an influential segment of pharmaceutical utilization for remedies & hygiene in the latest era. The first topic reviews the study on air sanitization ventilation & air sanitizer systems using laser ablated silver nanoparticles (inspired by 2020 Pandemic) directing to contamination of deadly biological particles. Intention of this investigation is to validate possible antiviral silver nanoparticles construction to be distributed by retention, to abate the aggravation of breathing organs flu. The underlying description of investigation consists of bibliometric reasoning of the review of the outcome of silver nanoparticles on the sterilization of viral ailments. The investigation will deliberate the approach of use of laser ablated silver nanoparticles for anti-actions. The chapter outcomes in the fascinating utilization of silver nanoparticles for pharmaceutical purposes for contagious diseases, viruses or bacteria and devotes to the upgradation of therapeutic education to safeguard health care workers from threatening viruses at therapeutic organizations. Morally, the investigation will obtain a hygienic scheme, which might be installed at every communal or individual places cost-effectively including silver nanoparticles (because of their therapeutic properties). The second section of investigation considers distinct techniques for manufacturing silver nanoparticles. The various schemes have been compared based on their pros & cons. The method of laser ablation for generating nanoparticles underwater is briefed. The intention of this part is to disclose the current & anticipation probabilities of the process - laser ablation, as a profitable and eco-favorable innovation for manufacturing silver nanoparticle in liquid solutions. The chapter is motivated by two of our reviewed papers i.e., “Antibacterial and anti-viral effects of silver nanoparticles in medicine against covid 19” and “Methods for obtaining silver nanoparticles”.