Now showing 1 - 10 of 83
  • Publication
    New device for air disinfection with a shielded UV radiation and ozone
    (2021-01-01) ;
    Mezule, L.
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    Pizica, V.
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    Denisova, V.
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    Skudra, A.
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    ; ;
    Juhna, T.
    Received: February 1st, 2021 ; Accepted: May 2nd, 2021 ; Published: May 7th, 2021 ; Correspondence: andris.martinovs@rta.lv Indoor air disinfection has become particularly relevant recently because of the Covid-19 pandemics. A shielded device for air and surface disinfection with UV radiation and ozone has been developed. It contains 28 low intensity (11 W) UV lamps (254 nm) in a specially designed three-dimensional grid to provide a large flow cross-sectional area and long path for the air particles to be irradiated. The device can be used in medical institutions, veterinary clinics, manufacturing plants, public premises, poultry, and livestock farms. It does not generate air-ions and ozone concentrations do not exceed the allowed 8-hour average values. The large number of UV lamps and powerful fans ensure air disinfection in large rooms in a relatively short time (400 m3 h -1 ). Simultaneously, the floor surface under the appliance is disinfected. Disinfection efficiency tests demonstrated 99.9999% reduction for Escherichia coli, Staphylococcus aureus and Pseudomonas phage Φ6 aerosols within a single transfer through the system (10 seconds of treatment). The housing of the device protects from direct UV radiation; therefore, people can be in the room during the operation of the device.
  • Publication
    LASER ABLATION OF PAINT COATINGS IN INDUSTRY
    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
    Finite element modeling of laser aluminum marking
    (2021) ;
    N Angelov
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    I Draganov
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    A Atanasov
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    A Lengerov
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    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
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    ; ;
    Martins Sperga
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    Ingus Dilevka
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    Artis Vitins
    Scopus© Citations 1
  • Publication
    PRELIMINARY NUMERICAL ANALYSIS FOR THE ROLE OF SPEED ONTO LASER TECHNOLOGICAL PROCESSES
    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
    INNOVATIVE LASER TECHNOLOGY IN TEXTILE INDUSTRY: MARKING AND ENGRAVING
    (2017)
    Yordanka Angelova
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    The advent of laser technology in textiles industry has established a new innovative solution, which successfully prevents some of the weaknesses in the conventional technologies. Lasers are being used in Laser Marking (Only the surface of fabric is processed, fading), Laser Engraving (Controlled cutting to depth). It has been used extensively as the replacement of some conventional dry processes like sand blasting, hand sanding, destroying, and grinding etc., which are potentially harmful and disadvantageous for the environment. The article considers some innovative laser technologies, such as marking and engraving on various textile materials. The laser applications for leather and textile processing were analysed. The report overviews systems and ways of laser marking and engraving implementations. Classification of markings was proposed. The advantages of laser marking and engraving technologies in textile fields were pointed.
    Scopus© Citations 15
  • Publication
    ROLE OF LASERS IN CONTROL OF ENVIRONMENTAL QUALITY
    (2022-05-07)
    Khrystyna Yartym
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    Mariia Liakhovych
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    Andrii Kos
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    Anastasiia Ischenko
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    Tatiana Yefimova
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    This article describes different ways of using laser technology in different fields of science. In biology, lasers are used to study the microstructure of cells, their organelles (living cells and their preparations). In medicine they are used for a special type of surgery. With the development of lasers, they have become safer, easier to use. Technologies for the use of lasers in medicine have also improved to such a level that they cause almost no complications after their application.
  • Publication
    SPECIAL SPLINE APPROXIMATION FOR THE SOLUTION OF THE NON-STATIONARY 3-D MASS TRANSFER PROBLEM
    In this paper we consider the conservative averaging method (CAM) with special spline approximation for solving the non-stationary 3-D mass transfer problem. The special hyperbolic type spline, which interpolates the middle integral values of piece-wise smooth function is used. With the help of these splines the initial-boundary value problem (IBVP) of mathematical physics in 3-D domain with respect to one coordinate is reduced to problems for system of equations in 2-D domain. This procedure allows reduce also the 2-D problem to a 1-D problem and thus the solution of the approximated problem can be obtained analytically. The accuracy of the approximated solution for the special 1-D IBVP is compared with the exact solution of the studied problem obtained with the Fourier series method. The numerical solution is compared with the spline solution. The above-mentioned method has extensive physical applications, related to mass and heat transfer problems in 3-D domains.
  • Publication
    Antibacterial and anti-viral effects of silver nanoparticles in medicine against COVID-19—a review
    (2020) ;
    Ivaylo Balchev
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    Risham Singh Ghalot
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    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