Now showing 1 - 10 of 10
  • 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 HARDENING USE FEATURES ON STEEL C45
    (2019-01-01) ;
    Teirumnieks, N.
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    The paper investigates and describes laser hardening of steels, types of lasers, important parameters of laser hardening, as well as steels that are suitable for laser hardening process. The laser hardening process of steel C45 samples is described, the analysis of the results is described and the result is summarized. The results of the experiments show that laser hardening is capable of meeting the relevant requirements and quality parameters in steel C45 hardening.
  • Publication
    THE EFFECT OF 3D PRINTING ON A TEXTILE FABRIC
    3D printing capabilities are also used in the fashion and textile industries. 3D printed textiles are a new opportunity to create an individual design. Traditional textile structures can be interpreted using 3D printing technologies and materials. One of the most important factors associated with the use of 3D printing technology is to reduce the impact of processing on the physical properties of textile fabrics. Availability of 3D printers at Rezekne Academy of Technologies (RTA) provides experimental work with fabrics of different thickness and fibres as well as different filaments. This study is based on the analysis of synthetic fibre cloth processing and the effect of 3D printing parameters on textile materials. By applying successive layers of materials, the interaction between 3D printing and textiles is studied. In terms of adhesion and stability, the best adhesion parameters for a particular type of fabric are determined by analysing the type of the fabric. The variance analysis method is used to process the research results.
  • Publication
    CO2 LASER HEAD NOZZLE FLOW ANALYSIS AND MODERNIZATION
    (2021)
    Ilja Suckovs
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    Raitis Rudziss
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    With the passage of time and the development of technology, more applications are found in CNC controls with CO2 laser equipment. Laser machines with a CO2 source are increasingly distributed in woodworking and synthetic materials processing. Laser equipment makes it possible to produce high-quality and geometrically accurate products. The quality of the surface to be processed is directly related to the air flow intensity, which prevents sublimated particles burn to processed surface. The aim of the study is to increase air flow intensity by upgrading the internal design of the head nozzle. Simulations are created for modernized head nozzle that help to analyze the resulting data. Cutting and engraving is performed for wood material in working range for the head nozzle tests.
  • Publication
    Scopus© Citations 2
  • Publication
    Influence of rubber ageing on damping capacity of rubber vibration absorber
    (2018)
    Svetlana Polukoshko
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    The vibration dampers, shock absorbers, seismic isolation, bearing seals, compensation devices are widely applied in civil engineering, machine manufacturing and shipbuilding, aviation and aerospace engineering. For these details fabrication elastomeric materials are used. Rubber and rubber-like materials (elastomers) have the capability of absorbing input energy much better than other engineering materials. Elastomeric materials give many engineering advantages due to their high elasticity, good dynamic properties, low volume compressibility, a linear relationship between stress and strain at small and middle deformation, resistance to aggressive environmental factors. The disadvantage of elastomeric materials is ageing, i.e. changing their mechanical properties over time and lowering their operational capability. In given paper the influence of ageing of elastomeric materials on the damping properties of shock absorbers is considered based on the mechanical models of elastomers - Maxwell and Burgers modes.
    Scopus© Citations 6
  • Publication
    EXPERIMENTAL STUDYING OF MECHANICAL-AND- PHYSICAL PROPERTIES OF RUBBER DURING AGEING
    (2019)
    Svetlana Polukoshko
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    Elastomeric materials, both natural rubber and synthetic, are widely used in industry and civil engineering, due to their unique properties: high elasticity, low volume compressibility, capability to absorb and dissipate input energy, a linear relationship between stress and strain up to strain of 15% ÷ 20%, resistance to aggressive environmental factors. Different kind of compensation devices, vibration dampers, shock absorbers are fabricated from rubber materials.At the same time the elastomeric materials nonreversible change their properties over time, this disadvantage is called ageing.In given paper the results of experimental studying of the influence of aging on the physical-and-mechanical properties of polyurethane rubber is presented. The samples of cylindrical form were prepared from soft flexible polyurethane rubber Xenias PX30 and subjected to the artificial ageing. Accelerated aging of samples was fulfilled in accordance with European standard ISO 188:2011 (Rubber, vulcanized or thermoplastic - Accelerated ageing and heat resistance tests).The changing of volume, Shore A hardness, elastic rebound coefficient and static elasticity modulus under compression were investigated. Experiments showed the volume decrease, hardness shore increasing, elastic rebound increase and compression modulus under static loading increasing. This data are necessary for correct designing of the compensation devices to provide their working properties during all service life.
  • Publication
    3D SCANNERS. DIVERSITY AND OPERATING PRINCIPLES
    (2023)
    Aksjonovs, Artēmijs
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    The paper deals with existing 3D scanners classification and types. Each 3D scanner given the principle of operation. It examines the scope of application of different type scanners advantages and disadvantages. The aim was based on this data to create a 3D scanner prototype, by means of which an ordinary user can conveniently and easily scan a small, straightforward form objects.
  • Publication
    RESEARCH OF LASER MARKING AND ENGRAVING ON BRASS ALLOY 260
    Brass Alloy 260 is widely used in mechanical engineering (odometer contacts, radiator cores), electrical engineering (electrical connectors, screw shells), plumbing (bathroom fixtures), consumers (watch parts, buttons, lamps) etc. The paper presents an analysis of the laser marking and engraving process. The ability Rofin powerline f20 laser system to engrave on Brass Alloy 260 is described. Recommendations are given on choosing the right parameters for laser marking and engraving of Brass Alloy 260 products.
    Scopus© Citations 1