Lazov, Lyubomir

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Preferred name
Lazov, Lyubomir
Official Name
Lazov, Lyubomir
Alternative Name
Lyubomir Lazov
Lazov, Lyubomir Kostadimov
Main Affiliation
Email
lyubomir.lazov@rta.lv
Scopus Author ID
55384203700
Researcher ID
E-6011-2012

Research Output

Now showing 1 - 10 of 28
  • Publication
    Modification of Aluminum 1050 and 2219 Alloys Using CuBr Nanosecond Laser for Hydrophobic and Hydrophilic Properties
    (2023)
    Antons, Pacejs 
    ;
    Emil Yankov
    ;
    Adijāns, Imants 
    ;
    Teirumnieks, Edmunds 
    ;
    Lazov, Lyubomir 
    This study investigates the use of a CuBr vapor nanosecond laser with a 510 nm/578.2 nm wavelength for the surface treatment of 1050 aluminum and 2219 aluminum alloys. Laser-induced periodic surface structuring was used to optimize processing parameters to achieve hydrophobic and hydrophilic properties on the surface. The wetting properties were measured and the roughness results (Ra, Rz, Rq) evaluated. Prior to and after laser treatment, surface wetting and roughness changes were investigated. The wetting study showed that the maximum contact angle between a droplet of deionized water and the treated surface can be reached between more than 140 degrees and less than 10 degrees, which, respectively, is a superhydrophobic and superhydrophilic surface. Compared with the untreated surface, wetting increased by more than 2 times and decreased by more than 8 times. Overall, experiments show the dependence of wetting properties on laser input parameters such as scan speed and scan line distance with different delivered energy amounts. This study demonstrates the possibility of laser parameter optimizations which do not require auxiliary gases and additional processing of the resulting surfaces to obtain different wetting properties on the surface. The findings described in this article suggest that the CuBr laser surface treatment method is a promising method for industrial applications where surfaces with special wetting and roughness properties are required, for example, the laser marking of the serial number of parts used in wet environments such as aerospace, shipbuilding, and defense industries.
  • Publication
    Effect of Laser Marking Speed, Power and Pitch on Hardness and Roughness of Aisi 304l
    (2023)
    Lazov, Lyubomir 
    ;
    Teirumnieks, Edmunds 
    ;
    Emil Yankov
    ;
    Nikolay Angelov
    ;
    Adijāns, Imants 
    ;
    Antons, Pacejs 
    In this study, an experiment was conducted to change the technological properties of the surface by infra-red laser marking. The influence of power, speed and raster step was investigated. These parameters during laser marking of AISI 304L steel have a significant change on the microhardness and surface roughness. It was found that high stiffness is achieved at higher powers and small pitch. An analysis of the results showed that as the raster step increases, the roughness of the marked sample decreases. The influence of linear energy density and overlap factor on the process was also investigated. The microhardness of the treated surfaces increases with an increase in the linear energy density and the overlap coefficient, and in the first case the dependence is almost linear, and in the second - non-linear.
  • Publication
    LASER ABLATION OF PAINT COATINGS IN INDUSTRY
    (2021)
    Teirumnieks, Edmunds 
    ;
    Lazov, Lyubomir 
    ;
    Nikolay Angelov
    ;
    Teirumnieka, Ērika 
    ;
    Adijāns, Imants 
    ;
    Antons, Pacejs 
    A comparison is made between the laser and sandblasting methods for removing paint from industrial facilities. The advantages of laser ablation are discussed. The possibilities of laser paint removal systems - stationary and moving - are shown. The main factors influencing the laser ablation process and the indicators that determine the quality of the obtained surface are systematized. Researchers' publications on this technological process are analyzed.
  • Publication
    Silver Nanoparticles - Preparation Methods and Anti-Bacterial/Viral Remedy Impacts against COVID 19
    (2021)
    Lazov, Lyubomir 
    ;
    Risham Singh Ghalot
    ;
    Teirumnieks, Edmunds 
    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”.
  • Publication
    INVESTIGATION OF THE INFLUENCE OF THE NUMBER OF REPETITIONS ON THE PROCESS OF LASER MARKING OF HS6-5-2-5 STEEL
    (2021)
    Lazov, Lyubomir 
    ;
    Nikolay Angelov
    ;
    Teirumnieks, Edmunds 
    Today, methods for marking parts and components in industrial production are constantly improving, and they must meet several basic criteria for active traceability by consumers. The parameter that is of paramount importance for the quality of the marking is related to the contrast of the marked sign or QR code. To achieve optimal contrast, a number of technological factors and the functional relationships between them must be taken into account.The report examines the role of the number of repetitions on contrast in raster marking of HS6-5-2-5 tool steel products. The dependences of the number of repetitions on the speed and frequency are also taken into account - the main factors in the process of laser ablation. Graphs of the depth of the marking are drawn depending on the number of repetitions and the linear density of the pulses. The experiments were made with a fiber laser. By the performed analyses the working intervals of processing between the studied factors are deduced, allowing to achieve the desired optimal result.
    Scopus© Citations 1
  • Publication
    Finite element modeling of laser aluminum marking
    (2021)
    Lazov, Lyubomir 
    ;
    N Angelov
    ;
    Teirumnieks, Edmunds 
    ;
    I Draganov
    ;
    A Lengerov
    ;
    A Atanasov
    ;
    I Balchev
    This work makes use of the finite element model, whose results are validated by experiments. The effect is discussed of the speed on the laser marking process. Numerical experiments are performed to determine the temperature fields produced by laser pulses on samples of aluminum, a material with wide industrial uses. The numerical calculations are performed for the cases of a fiber laser and a CuBr laser. Plots are drawn of the temperature dependence on the speed for two power densities for both lasers. Preliminary working speed intervals are determined for the power densities used.
    Scopus© Citations 1
  • Publication
    Artificial Neural Networks: What Can They Learn about Color Laser Marking?
    (2018)
    Pavels Cacivkins
    ;
    Lazov, Lyubomir 
    ;
    Teirumnieks, Edmunds 
    ;
    Martins Sperga
    ;
    Ingus Dilevka
    ;
    Artis Vitins
    Color laser marking paves the way for many useful applications in modern industry - traceability, anticounterfeiting, etc. Laser marking of materials is an inherently difficult problem with no clear functional relationship between many technological parameters on the input and the results of processing on the output. Some processes cannot be well defined without the use of examples. In this paper we discuss the novel method of training artificial neural networks using real experimental color laser marking data for prediction of results. We conclude the paper by discussing the other potential applications of proposed solution in the field of laser materials processing.
    Scopus© Citations 1
  • Publication
    Investigation of Surface Structure in the Laser Marking Process as a Function of Speed and Raster Step
    (2023)
    Emil Yankov
    ;
    Lazov, Lyubomir 
    ;
    Teirumnieks, Edmunds 
    ;
    Nikolay Angelov
    ;
    Adijāns, Imants 
    ;
    Antons, Pacejs 
    In this research, an experiment was conducted to change the technological properties of the surface by laser marking. The influence of the speed v of 50 mm/s, 75 mm/s and 100 mm/s and the raster step Δx from 20 µm to 80 µm at a constant average power P = 19.2 W and pulse duration τ = 4 ns was investigated. These parameters during the laser marking of AISI 304L steel have a significant change in microhardness and surface roughness. High hardness was found to be achieved at higher powers and small pitch. Analysis of the results showed that as the raster step increases, the roughness of the marked sample decreases. The effect of linear energy density and overlap factor on the process was also investigated. The microhardness of the machined surfaces increases with an increase in the linear energy density and the overlap coefficient, in the first case the dependence is almost linear, and in the second - nonlinear. Varying the marking speed and raster pitch in laser surface texturing of AISI 304L steel has a significant effect on the surface hardness and roughness, changing HV from 260 HV to 766.5 HV and Ra from 1.75 µm to 4.3 µm, respectively, which are the subject of the present analysis. research.
  • Publication
    PRELIMINARY NUMERICAL ANALYSIS FOR THE ROLE OF SPEED ONTO LASER TECHNOLOGICAL PROCESSES
    (2019)
    Lazov, Lyubomir 
    ;
    Nikolay Angelov
    ;
    Teirumnieks, Edmunds 
    ;
    Teirumnieka, Ērika 
    Studying the impact of speed on a number of laser processes such as marking, engraving, cutting, welding and others is crucial for the optimization of these technological processes. The processing speed, along with the frequency of laser pulses and their duration, also determines the time of action in the processing area and hence the absorbed quantity of electromagnetic energy. Based on numerical experiments with specialized software TEMPERATURFELD3D, the report analyzes the temperature variation in the processing area as a function of speed. The researches were analyzed for processing with two types of lasers emitting in the visible and infrared areas of the electromagnetic spectrum and two types of steels (tool and structural). From the course of the obtained temperature fields the dependence of temperature on the speed at two power densities was obtained. The obtained results help to make a preliminary assessment the speed work intervals for the processes as laser marking, laser engraving, laser cutting, laser welding and others. In this way, it is assisted in building an optimal concept for the passing of a particular technological process in function of the laser source, the material and the type of the technological operation.
    Scopus© Citations 13
  • Publication
    Antibacterial and anti-viral effects of silver nanoparticles in medicine against COVID-19—a review
    (2020)
    Teirumnieks, Edmunds 
    ;
    Ivaylo Balchev
    ;
    Risham Singh Ghalot
    ;
    Lazov, Lyubomir 
    The article reviews the research on disinfecting the air through air filters and ventilation systems using silver nanoparticles (Ag NPs) (encouraged from the present situation of COVID-19) focusing on stopping the spreading of deadly viruses. The primary goal of the research is to demonstrate possible antiviral Ag NP formulations to be delivered by inhalation, to minimize the worsening of respiratory system infections. The basic design of the study includes a bibliometric analysis of the study of the effect of Ag NPs on the disinfection of viral infections. The research will discuss the idea of the use of laser ablation with Ag NPs for antiviral and antibacterial effects. The research article results in compelling evidence for the use of Ag NPs for medicinal purposes for infectious diseases/viruses and will contribute to the progress of medical science to protect healthcare workers from dangerous viruses at medical institutions. Practically, the research will generate a sterile system, which might be employed by every public or private institution economically with Ag NPs (because of their antimicrobial properties).
    Scopus© Citations 25