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Zaicevs, Edgars
Preferred name
Zaicevs, Edgars
Alternative Name
Edgars Zaicevs
Zaicevs, E
Email
edgars.zaicevs@rta.lv
ORCID
Scopus Author ID
57196454922
Researcher ID
GKE-1223-2022
Research Output
Now showing 1 - 9 of 9
- PublicationNew device for air disinfection with a shielded UV radiation and ozone(2021)
; ; ; ; Juhna, T.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. - PublicationRESEARCH OF LASER MARKING AND ENGRAVING ON BRASS ALLOY 260(2019)
; ; ; 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 - PublicationLaser hardening process optimization using FEM(2020)
; ; In given work a method for optimization of the process of laser hardening of steel parts is developed. The approach is based on the finite element method (FEM) using computer program “COMSOL Multiphysics” (module Heat Transfer in Solids) – software for multi-physical processes simulation. This method allows to reduce the number of laser hardening experiments, replacing them with numerical calculations, and to find the optimal parameters of the used laser equipment. To perform the calculations it is necessary to know the hardening temperature range of the particular steel grade, the martensite formation start temperature, the critical value of the cooling rate, the material density, the thermal conductivity k = k(T), the specific heat capacity Cp = Cp(T) and the surface reflectivity R = R(T, λ), where T temperature, λ – wavelength of laser beam. Depending on the laser power, the feed rates of the laser beam, the spot size and the distribution of energy in it, the temperature field is calculated for the steel part in different moments of time. Analysing these data it is possible to determine the thickness of the hardened layer or to predict damage to the material of a given steel part due to heat treatment. The method has been tested experimentally. - PublicationLASER HARDENING USE FEATURES ON STEEL C45(2019-01-01)
; - PublicationTHE EFFECT OF 3D PRINTING ON A TEXTILE FABRIC(2020)
; ; ; Gunta Salmane3D 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. - PublicationDetermination constants of 4-element reological model with rebound resilience method(2017)
; Scopus© Citations 2 - PublicationInfluence of rubber ageing on damping capacity of rubber vibration absorber(2018)
; 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 - PublicationEXPERIMENTAL STUDYING OF MECHANICAL-AND- PHYSICAL PROPERTIES OF RUBBER DURING AGEING(2019)
; 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. - Publication3D SCANNERS. DIVERSITY AND OPERATING PRINCIPLES(2017)
; Martinovs, AndrisThe 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.