The use of LEDs in lamps is promising for effective plant growth. Plant growth lamps are designed to create artificial lighting for agricultural crops. This work is devoted to the creation of a smart LED lamp with the ability to adjust the spectral composition of radiation depending on the stage of growth and the type of plant. A number of experiments were carried out to investigate the effect of various radiation parameters on the growth characteristics of dill, parsley, green onion and cucumber seeds. The optimal radiation parameters that contribute to the acceleration of the selected model plants growth were identified. Based on the results obtained, a multi-wavelength LED lamp with an adjustable radiation composition, including blue 440 nm and red 660 nm LEDs, was developed. In the lamp, the possibility of changing the spectral composition of radiation at different stages of growth was realized. Therefore, it is possible to change the light parameters in accordance with the obtained data on the development of crops.
Laser surface treatment is a complex process in which, under the influence of a laser, the surface of material melts, while changing its structure and properties. In this paper, we consider the simulation of the process and present the results of studying the influence of laser processing parameters on the dimensions of the melt pool. The main purpose of the study is to reveal the dependence of the depth of the melt pool, namely the thickness of the layer in which the mixing process of the components takes place, on the laser parameters. As a result of the study, it was found that after laser treatment of the surface of samples with a coating thickness of 20, 40 and 80 μm at a beam speed of 100 mm/s and power of 180 W, the coating material is completely mixed with the substrate. It is also shown that with the laser travel speed 400 and 800 mm/s and the power 180 W, there is no mixing of the components in the impact zone, since the energy input is not enough.
The results of a study of intermetallic coatings of the Al–Ti and Ni–Ti systems obtained using the method of cold gas-dynamic spraying on a titanium alloy substrate and laser processing are presented. The precursor coating was obtained by cold spray deposition of aluminum and nickel and then it was processed by a laser. The change in the composition and properties of the coating under different laser processing modes is shown. The structure and microhardness of the coating are investigated, and the results of X-ray phase analysis are presented.
This chapter presents the influence of powder bed laser scanning strategy on the crystallographic structure of the fused specimens 316 L, 321 stainless steel, and Alnico magnets. The main parameters affecting structure are as follows—laser power, stripe width, number of repeated passes with different power, and type of scanning (circle, bidirectional or interlaced, etc.). Changes in the crystallographic structure are studied with regard to melt pool geometry, surface temperature, and surface heat transfer. The correlation is shown between stripe width and laser beam focal spot diameter. Depending on the ratio between stripe width and laser beam focal spot diameter one can see growth elongated and oriented grains or quasi-equiaxed non-oriented grains. The influence of the energy input on the melt pool size and the microstructure of the sample is studied. The influence of the scanning mode (bidirectional and circular) on the temperature distribution in the sample and the microstructure of the sample made of Alnico alloy is considered. All these experimental and model examples clearly demonstrate that it is possible to produce a controllable structure during LPBF process building for advanced additive manufacturing.
In the article the features of the physical processes modeling of the ultrasonic wave interaction to the metal structures are considered. The mathematical model for calculating the acoustic field of a single element of a 32-element electromagnetic acoustic phased array of SV-waves is developed. The computer simulation of the process of reflection of the ultrasonic beam from a defect is carried out. The developed model allows to study the influence of the shape, size, location of defects in the plate, as well as the geometric parameters of the plate, on the formation of the reflected signal.
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