MM Science Journal, December 2019

December 2019

NARX-NN MODEL OF 2-DOF ROBOT ARM DYNAMICS DRIVEN BY FLUIDIC MUSCLES

Monika Trojanova, Alexander Hosovsky
Keywords: System Identification Toolbox | MLP (Multilayer Perceptron Network) | NARX (Nonlinear Autoregressive Exogenous) | identification | Planar Robotic Arm | Fluidic Muscles

The article contains the results of identification of manipulator arm dynamics that is driven by pneumatic artificial muscles (specifically, fluidic muscles). The NARX architecture model - a multilayer perceptron network (MLP model) was selected for identification. Simulations were realized using MATLAB, especially with use the System Identification Toolbox. The simulation results were tracked at 3 diff (…)

METHODOLOGY FOR RISK ASSESSMENT OF NOISE EFFECTS AT WORKPLACE

Michaela Balazikova, Miriam Andrejiova, Barbora Wysoczanska
Keywords: workplace safety | non-auditory noise effects | risk | noise

Noise is pervasive in everyday life and can cause two kinds of health effects - auditory and non-auditory health effects. The most investigated non-auditory health endpoints for noise exposure are perceived disturbance and annoyance, cognitive impairment (mainly in children), sleep disturbance, and cardiovascular health. The article presents a case study of non- auditory effects of noise on humans. This (…)

COMPARISON OF SELECTED MATERIALS INTENDED FOR THE MANUFACTURE OF PLASTIC HOLDER FOR REVERSE PARKING SENSOR WITH THE USE OF COMPUTER SIMULATION TOOLS

Petr Baron, Jakub Kascak
Keywords: shrinking | injection | analysis | Simulation of production processes

The article deals with suitability assessment of selected types of materials needed for the manufacture of plastic holder of parking sensor, which is located in the vehicle bumper. By applying the PTC Creo Mold Analysis simulation tool, the manufacturing process has been assessed to minimize potential errors affecting not only the appearance properties of the final part, but also its mechanical properti (…)

PROGRAM FOR CALCULATION OF WORM GEARING SYSTEM

Slavko Pavlenko, Luba Bicejova
Keywords: worm gear | worm | program

The aim of the paper is to point out to a possibility of program creation which would facilitate calculation of geometric dimensions of worm gearing system for students at secondary technical schools and universities as well as for employees working in the technical field with the following parameters: module, number of worm teeth, gear ratio, and coefficient of worm diameter. The paper contains a detai (…)

ANALYSIS OF THE FLAME FRONT GEOMETRY RESPECT TO THE NOX FORMATION

Andrii Kulikov, Miroslav Rimar, Marcel Fedak, Olha Kulikova
Keywords: ANSYS | natural gas | heating | burner | Boiler

Natural gas is one of the cleanest organic fuels, nevertheless, it produces pollutants in the combustion process. The major pollutants of the combustion in the atmosphere are carbon monoxide CO, nitrogen oxides NO, NO2, sulphur dioxide SO2 and hydrocarbons. The current article deals with the problematic of the high NOx formation rates under the high power operation. The object under research was a middl (…)

PLUNGER PRESSING SPEED LIKE THE MAIN FACTOR INFLUENCING OF THE MECHANICAL PROPERTIES OF DIE CASTING

Stefan Gaspar, Jan Pasko
Keywords: mechanical properties | plunger pressing speed | die casting

In the process of die casting the final quality of a cast is influenced by a great number of factors. The interpretation of the impact of the individual factors of die casting is based on the concept of the filling of a mould cavity. The issue of the filling of a die casting mould is complex due to the fact that the factors such as the cast structure and the mould thermal balance usually determine the r (…)

HYDROXYAPATITE AND ZINC OXIDE BASED TWO-LAYER COATING, DEPOSITED ON TI6AL4V SUBSTRATE

Leonid Sukhodub, Anton Panda, Luidmila Suchodub, Mariia Kumeda, Konstantyn Dyadyura, Iveta Pandova
Keywords: coating | alginate | zinc oxide | hydroxyapatite | Thermal substrate deposition

At first two-layer, HA-ZnO/Alg coating was obtained on the pre-anodized Ti6Al4V substrates by the thermal substrate deposition method (TSD). In the frame of this work, TSD method was at first applied for obtaining ZnO coating from aqueous alginate-containing solutions on a pre-deposited OH layer. XRD, SEM analyzes show that the biopolymer has a significant influence on the coatings formation, their mor (…)

THE CONDITIONS FOR OBTAINING SELF-ORGANIZED STRUCTURES ON THE TRIBOLOGICAL SURFACES OF COMPOSITE MATERIALS BASED ON POLYTETRAFLUOROETHYLENE WHICH IS USED IN AUTOMOTIVE AND OTHER DEMANDING TECHNOLOGIES

Anton Panda, Konstiantyn Dyadyura, Marta Harnicarova, Jan Valicek, Iveta Pandova, Zuzana Palkova
Keywords: polytetrafluoroethylene. | physical and mechanical properties | principles of self-organization and nonequilibrium thermodynamics | composite material | wear

The paper discusses a self-organization phenomenon, physical and chemical aspects of friction, and the methods of friction control using advanced polymer composites based on polytetrafluoroethylene (PTFE). The article also concerns a generic physical and an engineering approach to the development of new wear-resistant polymer composites with modified fibers filler. The influence of the mechanochemica (…)

INNOVATION OF THE GAS MELTING FURNACE MONITORING SYSTEM

Luboslav Straka, Slavko Pavlenko, Peter Michalik, Matej Hrabcak
Keywords: efficiency. | gas melting furnace | operating | monitoring

There are increased demands for safe, reliable and economically efficient operation of modern technical devices nowadays. These technical devices need an appropriate monitoring system in order to fulfil all the requirements. This consequently monitors their activity while providing appropriate information on operating parameters. As a result of them, the control system of a technical device can perform (…)

PREDICTING THE BEHAVIOR OF THE VEHICLE IN A FRONTAL COLLISION INTO RIGID BARRIER BY USING A SYSTEM IDENTIFICATION TOOLBOX

Jozef Kmec, Jozef Pavelka, Jaroslav Soltes
Keywords: Transfer function model. | Polynomial model | Process model with transfer function | state-space model | System Identification Toolbox | Matlab

The main objective of this paper is to establish models of measured real-time data that are obtained in a frontal impact of a vehicle into the rigid barrier. When it tcomes to modeling the vehicle crash we can distinguish two approaches. The first one utilizes CAE (Computer Aided Engineering) software including FEA (Finite Element Analysis) while the second one is based on the System Identification To (…)

OPTIMIZATION OF FIVE-AXIS FINISH MILLING USING A VIRTUAL MACHINE TOOL

Petr Kolar, Matej Sulitka, Vojtech Matyska, Petr Fojtu
Keywords: surface quality | machining productivity | control system | interpolator | milling accuracy | virtual machine tool | finishing milling | Five-axis machining

Five-axis finish milling is a complex process. The requested surface quality and accuracy must be produced in the shortest possible time. The three main process characteristics - quality, accuracy and machining time - are closely related one to each other. They are affected by the dynamic properties of the machine tool structure, the feed drive properties including cascade control, the control system in (…)

COMPUTER-AIDED DESIGN OF TECHNOLOGY FOR PRODUCING SOLID LUBRICATING COATING ON TOOL STEEL

Alexander Shmatov, Lubomir Soos, Zdenko Krajny
Keywords: tool steel | solid lubricating coating | Thermo-hydrochemical treatment

This article deals with the new method for producing solid lubricating coatings on steel tools by thermo-hydrochemical treatment (THCT). The results of investigation of tribological properties of the coatings fabricated on high carbon steel of У8 grade (0,8 wt.%С) using THCT method are presented. The composition of the medium and the temperature and the time parameters of THCT process were optimized by (…)

UNIQUE APPLICATIONS OF OPTICAL PROPERTIES OF SILICON NANOSTRUCTURES

Yury Ryabchikov
Keywords: biological application | photoluminescence | optical properties | porous silicon | laser ablation | silicon nanoparticles

Silicon nanostructures can be prepared by different methods that considerably change their optical properties depending on experimental conditions. They are also very sensitive to molecular environment and external influences that can be used for multiple applications in different areas. Silicon nanostructures prepared by laser ablation show large perspectives for molecular sensing and biomedical applic (…)

IMPACT OF THERMAL BRIDGES ON THERMAL PROPERTIES OF THE OLD POULTRY HOUSES STRUCTURES

Petr Junga, Petr Travnicek, Juraj Ruzbarsky
Keywords: thermal defect | infrared thermography | construction

The paper is focused on qualitative and quantitative evaluation of the thermal properties and thermal bridges of the old poultry structures. The results of the paper claim poor thermal properties most of the constructions. Qualitative detection of thermal defects with the utilization of infrared thermography claimed the most significant thermal bridges on uninsulated socle and flooring, straining band o (…)

LASER FACILITY SAFETY CONTROL SYSTEM

Pavel Trojanek, Martina Rehakova, Pavel Crha
Keywords: PLC | Programmable Logic Controller | laser beam distribution | Laser | Interlock | control system | safety

A Safety Laser Interlock System was required for the Laser Laboratories in the HiLASE Centre in Dolni Brezany. The goal of the work was to develop a universal Laser Interlock System, which would control all the laboratories and the interlocks of multiple lasers with different powers and wavelengths in the laser laboratories in compliance with ISO EN 13849-1, Safety Performance Level PLe. The Safety Cont (…)

DESIGN PROPOSAL OF DIMENSIONS OF SLOTS BY DIGITALIZATION OF STANDARDIZED DIMENSIONS OF KEY

Luba Bicejova, Slavko Pavlenko
Keywords: hub | tight keys | Applications

The paper describes created applications for matching the dimensions of tight keys to shafts and design proposal of a slot for tight keys in the shaft and in the hub. The designed application determines basic dimensions in dependence on shaft diameter: breadth, height of the key and specifies the depth of the slot in the shaft and in the hub with corresponding marginal deviations of dimensions. The appl (…)

THE INFLUENCE OF ANISOTHERMAL HARDENING ON THE LOW CARBON STEEL PROPERTIES

Martin Podaril, Jan Majernik, Jiri Sal
Keywords: full-hardening | austenitisation | mechanical properties | heat treatment of metals

The purpose of hardening is the increase the hardness of the steel by creating an imbalanced structure. High hardness can be achieved by the formation of a martensitic structure. In some specific cases, we try to obtain a bainitic structure when hardening. In real hardening processes, a martensitic structure is usually achieved on the surface of the body, producing a mixture of martensite, bainite and o (…)

LASER INDUCED DAMAGE THRESHOLD OF SILICON WITH NATIVE AND ARTIFICIAL SIO2 LAYER

Juraj Sladek, Inam Mirza
Keywords: SiO2 thin film | Gaussian beam | silicon damage threshold | laser spot size | ultra-short laser ablation

Spot size measurements of a 260 fs, 1030 nm focused spatially Gaussian pulsed laser beam were performed on a Silicon surface with native and thermally grown SiO2 layers using a widely known method of evaluating laser beam energy dependent damage area. Single pulse laser induced damage thresholds of both samples were also measured. Modification of the thermally grown SiO2 layer was analyzed in detail us (…)

ANALYSIS OF BAR FEEDING INTO THE DRAWING TOOL

Jan Rihacek, Kamil Podany, David Kabilka, Libor Mrna
Keywords: CK67 steel | buckling stability | bar drawing | numerical simulation | ANSYS

The paper deals with a study of buckling behaviour of a bar, which is fed into the drawing tool in the production of drawn bar. When the undrawn bar is inserting into the two-die drawing tool by using hydraulic feeding collets, it can be buckled and stuffed between dies. Accordingly, basic parameters, such as a maximum possible buckling length, have to be found. Due to a specific shape of the drawn bar (…)

OPTO-MECHANICAL SYSTEM FOR LASER BEAM DISTRIBUTION

Karolina Macuchova, Jan Hermanek, Martina Rehakova
Keywords: HiLASE | vacuum chamber | opto-mechanical design | high-power laser | laser beam distribution | Laser facility

Laser beam distribution requires complex opto-mechanical system allowing safe and precise delivery of different laser beams from hall laboratories to experimental workstations developed within the HiLASE project of the IOP in the Czech Republic. The unique nature of new generation of HiLASE high energy diode-pumped solid state laser systems with high repetition rates requires advanced design approach. W (…)

ROBOTIC ARM HUMAN-MACHINE INTERFACE FOR LASER SHOCK PEENING APPLICATIONS

Marek Bohm, Jan kaufman, Jan Brajer, Danijela Rostohar
Keywords: online programming | LabView | industrial robotic arm | human-machine interface | Laser Shock Peening

The HiLASE Centre is equipped with a Laser Shock Peening station (LSP). LSP is a surface enhancing technique and it is used to prolong the fatigue life of metallic components. Part of the station is a FANUC M-20iA/20M 6-axis industrial robotic arm equipped with an R-30iB controller. The robotic arm is used to handle the LSP samples In order to facilitate the utilisation of the LSP station at the HiLASE (…)

EUV SOURCE AT HiLASE: THE STATE OF THE ART

Chiara Liberatore, Martin Duda, Pawel Sikocinski, Michal Chyla, Akira Endo, Martin Smrz, Tomas Mocek
Keywords: EUV lithography | water window | gas target | laser produced plasma | ellipsoidal grazing mirror | tabletop soft x-ray source | EUV

An overview of the Extreme Ultraviolet (EUV) source to be constructed in the frame of the Czech national R&D project HiLASE (High average power pulsed LASErs) is presented. The HiLASE EUV source will be devoted to industrial and medical applications, as well as to fundamental studies (such as the chemistry of polymers). This wide variety of different applications depends on the possibility of targeting (…)

COMPOSITE-TO-METAL TUBULAR LAP JOINT UNDER TORSIONAL LOADING

Petr Bernardin, Frantisek Sedlacek, Vaclava Lasova, Radek Kottner
Keywords: identification | damage modelling | Scotch-Weld DP490 | finite element | composite-to-metal | Bonded joint

During the damage evolution of bonded joints, different modes of failure can be detected. These modes include pure modes (Mode I, Mode II, Mode III) or their combinations (Mixed-mode) according to the type and the direction of loading. Some scientifically validated test methods are commonly used to obtain the fracture toughness by loading under pure Mode I, Mode II and their Mixed-mode. Some test method (…)

EFFECT OF THE DYNAMIC REFLECTIVITY ON LASER ENERGY ABSORPTION BY ZINC: NUMERICAL TWO-TEMPERATURE MODELING

Sergey Lizunov, Vladimir Zhukov, Alexander Bulgakov, Nadezhda Bulgakova
Keywords: finite difference method | two-temperature model | numerical modeling | electron heat conductivity | dynamic reflectivity | zinc | ultrafast laser

The optical response of metal surfaces to high-power laser excitation (HPLE) is one of important topics of laser-matter interaction, which remains to be poorly understood. It is known that certain metals, which are well reflective at normal conditions, become considerably absorbing during irradiation by ultrashort high-power lasers. Reflectivity of such metals during the irradiation stage is a key param (…)

DESIGN OF CNC MILLING MACHINE AS A BASE OF INDUSTRY 4.0 ENTERPRISE

Martin Sevic, Petr Keller
Keywords: Arduino | GRBL | industry 4.0 | smart factory | CNC milling machine

This article deals with a designing of one part of a smart factory model with the Industry 4.0 principles. It is a three-axis CNC milling machine with automated changes of tools and workpieces. The emerging factory is not controlled centrally, but each facility has its own control system and communicates with other facilities via IoT – Internet of Things principle. The machine tool is designed to mach (…)

LASER INDUCED DAMAGE THRESHOLD TESTING AT HILASE

pavel Cech, Jan Vanda, Mihai-George Muresan, Martin Mydlar, Katerina Pilna, Jan Brajer
Keywords: AA5083 | ISO | laser testing | laser damage | Laser | LIDT

More powerful and challenging laser systems are built to meet the need of evolving technology, reflecting demands coming from both industry and research areas. Laser damage is a key parameter for all components in such high-power laser system, establishing limits of maximum achievable energy in laser beam, and consequently the power of the system. As a value for all optical components, this is represent (…)

EFFECT OF SELECTED FACTORS ON MASS CONCENTRATION OF AIRBORNE DUST DURING WOOD SANDING

Miroslav Dado, Lucia Mikusova, Marian Schwarz, Richard Hnilica
Keywords: photometer | workplace air | real-time measurement | concentration | aerosol | safety

Sanding with handheld powered tools has been recognized as one of the most significant factor in personal exposure to wood dust in the woodworking industry. The aim of this study was to investigate the effects of wood species and grain size of abrasive on wood removal and mass concentration of wood dust emitted by a random orbit sander. Experimental study was designed as 4x4 full factorial experiments. (…)

MULTI-CRITERIA GROUP DECISION MAKING IN THE SUPPLIER SELECTION OF CAPITAL PARTS

Marcio Rodrigues, Eva Sirova
Keywords: spare parts | reliability | maintenance | group decision making process | AHP

Reaching a consensus in strategic and key decision processes always have been a big challenge in top management in enterprises globally, as they are required to make decisions much more accurate and quicker due to the increasing amount of inputs in the current reality of Industry 4.0. This article presents a case study of a multi-criteria group decision making (MCGDM) model for the supplier selection of (…)

THERMOELASTIC RESPONSE OF METALS AT DIFFERENT LOADING RATES

Radek Prochazka, Sylwia Rzepa, Pavel Konopik
Keywords: loading rate effect | thermoelastic stress analysis (TSA) | thermoelasticity

This paper deals with the thermoelastic response of ferrous and non-ferrous metals at different loading rates. The goal is to predict the stress-strain response based on temperature changes caused by adiabatic processes. These data are intended to be used for non-destructive full-field thermal stress analysis (TSA). The influence of strain rate on temperature was investigated in cyclically loaded dog (…)

SOLID AEROSOL– SOURCE OF OCCUPATIONAL DISEASES

Juraj Glatz, Zuzana Kotianova, Michal Gorzas
Keywords: exposure | concentration | occupational diseases | solid aerosols | safety

Measurements of solid aerosol concentrations are important tools to monitor air conditions at the workplace. In particular, the requirement for the workplace air quality management is necessary to prevent health damage and occupational diseases in exposed jobs. In this case, exceeded limit values for the concentration of solid aerosols were measured for all exposed workers. If such concentrations persis (…)

THE RESULTS OF THEORETICAL AND EXPERIMENTAL STUDIES OF TRIBOTECHNICAL PURPOSES COMPOSITES ON THE BASIS OF EPOXY COMPOSITE MATERIAL

Anton Panda, Konstiantyn Dyadyura, Petro Savchuk, Vitalii Kashytskyi, Viktoria Malets, Jan Valicek, Marta Harnicarova, Iveta Pandova, Lukas Androvic, Milena Kusnerova
Keywords: mechanical properties | thermal vacuum technology | molding | adhesion | Polymer composites

The results of theoretical and experimental studies of tribotechnical purposes composites on the basis of polytetrafluoroethylene (PTFE) and epoxy composite material with fillers of different chemical nature are given. The results have been obtained that prove that the introduction of carbon fiber of optimum length ensures the formation of a composite structure in which the fibers are evenly distributed (…)

MATERIAL SELECTION OF BLANKING TOOL BY USING A STATISTICAL METHOD

Tomas Holota, Maria Holiencinova, Martin Kotus, Stefan Mihina
Keywords: materials | FDMM method | blanking tool | blanking process | electro-slag remelting steel

The material of blanking tool was identified as one of the negative factors affecting high non-conformance and downtime in the blanking process. The aim of this paper was to choose a suitable alternative to the original material of blanking tool for achieving a longer operating tool life, and thus enhance the effectiveness and efficiency of the blanking process. Recommended materials by supplier were Ca (…)

DRAFT DESIGN SOLUTION FOR AUTOMATED 3D SCANNING OF PERSONS

Radomir Mendricky, Vratislav Maly
Keywords: Scanner Sense | automated scanning of persons | digitization | 3D scanning | construction design

This article deals with a process of designing an inexpensive device for automated scanning of people and large objects. The attention is paid to selection of technical solution of individual system components, from construction to calculation for motors of individual movement axes. The result is a device that allows automated digitization of objects with up to two metres of height, using simple and aff (…)

CURRENT ADVANCES IN HIGH AVERAGE POWER DIODE-PUMPED LASERS

Martin Hanus, Martin Divoky, Petr Navratil, Michal Chyla, Jan Pilar, Ondrej denk, Antonio Lucianetti
Keywords: Laser | diode | power | High

In the last two decades, the price of the laser diodes significantly dropped and made them an energy-effective solution for pumping high energy class high average power solid-state lasers. This is a significant advantage for the potential use of such lasers in industry, where operation cost is considered. The efficiency of such diode-pumped lasers is much higher compared to the previous generation of fl (…)

PROCESSING AND DIGITALIZATION OF VALUES OF GEOMETRIC TOLERANCES

Matej Hrabcak, Luba Bicejova, Slavko pavlenko
Keywords: application | digitalization | geometric tolerances

Achievement of desired service life, of correct and reliable function as well as meeting demands regarding replacement of engineering products requires observance of exact dimensions of functional areas as well as accuracy of geometrical shape, direction, reciprocal position of areas and of other elements of components. Tolerance of shape, of direction, of position and of flapping is commonly referred t (…)

NUMERICAL SIMULATIONS OF TEMPERATURE DYNAMICS DURING CW LASER IRRADIATION OF SILICON MICROSCALE STRIPS ON A DIELECTRIC SUBSTRATE

Jiri Beranek, Nadezhda Bulgakova
Keywords: implicit scheme | finite difference method | melting | amorphous silicon | laser modification | heat flow equation | numerical modeling

The numerical model presented in this article describes the heating of a thin strip of amorphous silicon on glass substrate by a continuous-wave Ar+ laser. The heat flow equation is solved using a finite difference method based on the implicit scheme with splitting by coordinates. A short overview of the methods of numerical analysis is given and the finite difference method is described in details incl (…)

ANTENNA-LIKE EFFECT INDUCED BY SURFACE DEFECTS UPON ULTRASHORT LASER NANOSTRUCTURING OF SILICON

Chiara Liberatore, Jan Hrabovsky, Inam Mirza, Alexander Bulgakov, Nadezhda Bulgakova
Keywords: periodic nanostructures | light scattering | antenna-like effect | surface defects | silicon | ultrashort laser pulses

Silicon is one of the most used materials in nanostructure research and in a wide range of high-technological applications spanning from the fine chemical industry to medicine and to semiconductor electronics. The processes underlying laser-induced nanostructuring of Si surfaces are still not fully understood. In particular, it is not completely clear how individual surface defects contribute to generat (…)

INFLUENCE OF GRAPHITE TOOL ELECTRODE SHAPE ON TWR AND MRR AT EDM

Luboslav Straka, Gabriel Dittrich
Keywords: Electrical Discharge Machining (EDM) | Material Removal Rate (MRR) | Tool Wear Rate (TWR) | Tool Electrode (TE)

Electrical Discharge Machining (EDM) is one of progressively developing machining technology. Its advantage over other progressive machining technologies is the high achieved accuracy of the machined surface. Moreover, in this case, it is machining without force, which means that the mechanical properties of the material to be machined do not impose almost any limits. However, during EDM, the material i (…)

CHARACTERIZATION OF CHIRPED VOLUME BRAGG GRATINGS - COMPACT LASER PULSE COMPRESSORS

Denisa Stepankova, Ondrej Novak, pawel Sikocinski, Lukas Roskot, Martin Smrz
Keywords:   Mg alloy | angular chirp | beam quality | diffraction efficiency | tunable laser | pulse compressor | chirped pulse amplification | Chirped volume Bragg grating

Increase in energy of ultrashort (picosecond, femtosecond) laser pulses is typically based on chirped pulse amplification (CPA) method. The nanojoule energy pulses are temporally stretched by several orders of magnitude prior amplification. The peak power is significantly decreased and the gain saturation and detrimental nonlinear optical effects, leading to the beam degradation, are avoided. Amplified (…)

KERR LENS MODE-LOCKED THIN DISK OSCILATOR DEVELOPMENT AT HILASE

Martin Cimrman, Martin Smrz
Keywords: high power laser | Kerr lens | laser oscillator | Yb:YAG | femtosecond laser | mode locking | Thin disk laser

Kerr lens mode locking (KLM) is an efficient way, how to generate ultrashort laser pulses. Employment of the KLM in thin disk-based lasers allows for generation of high average power ultrashort pulses reaching megawatts of peak power without adoption of the chirped pulse amplification technique. We demonstrate a small KLM Yb:YAG thin disk laser generating 240 fs long pulses close to 21 MHz repetition ra (…)

COMPACT, PICOSECOND, KW-CLASS THIN-DISK LASER PERLA FOR HI-TECH INDUSTRIAL APPLICATIONS

Martin Smrz, Michal Chyla, Jiri Muzik, Siva Nagisetty, Ondrej Novak
Keywords: high power laser | Yb:YAG

Ultrashort-pulse, high average power thin-disk lasers matured and became efficient tools for precise material processing and hi-tech laser applications. Hilase centre developed a diode-pumped thin-disk laser platform for Yb:YAG regenerative amplifiers delivering pulse energy >40 mJ, pulse repetition rate up to 400 kHz, nearly diffraction-limited output beam, and average power reaching of >500 W. The pla (…)

JONES MATRIX POLARIMETRY FOR HIGH POWER LASER OPTICAL COMPONENTS

Ondrej Slezak, Antonio Lucianetti
Keywords: depolarization | Dichroism | Birefringence | ellipsometry | Polarimetry

The Jones matrix based polarimetric method suitable for the spatially resolved analysis of the thermally induced birefringence and dichroism in complex high-power laser optical systems is proposed. The measurement allows the characterization of the complete local Jones matrix of the optical components, or their sets. The method of extraction of the particular contributions of the linear and circular bir (…)

EXPERIMENTAL RESEARCHES OF THE PULSE GAS BARRIER FACE SEAL

Eduard Kuznetsov, Anton Panda, Volodymyr Nahornyi, Sitlana Vashchenko, Olga Aleksenko, Iryna Baranova, Iveta Pandova
Keywords: flow rate characteristics | pressure distribution | sealing rings | barrier gas | impulse seal

The article presents a promising non-contact face seal of the rotor of a dynamic machine. The principle of pulse balancing of the movable sealing ring is applied in the seal design. The design of the test equipment and seal samples, which were used to conduct comprehensive investigations of the seal in the operating range of speeds and pressures, are considerated. The analysis of the experimentally obta (…)

METHODOLOGY OF DEVELOPMENT AND VALIDATION OF SOFTWARE FOR SAFETY-RELATED PARTS OF CONTROL SYSTEMS IN STAGE TECHNOLOGY

Michal Drlik
Keywords: human factor | reasonably foreseeable misuse | safety-related software life cycle | safety integrity level | functional safety | stage safety | Theatre

The presented paper contributes to solution of safety assurance in complex mechatronic systems used in theatre stage technology. The aim is to solve the problem associated with reasonably foreseeable incorrect behaviour of persons and operators of these systems by application of safety measures respecting the nature of the specific conditions in which such mechanisms are being used. Special attention is (…)

IMPLEMENTATION OF THE DESIGNED PROGRAM FOR CALCULATION AND CHECK OF CHAIN GEARS

Jozef Mascenik
Keywords: strength | design | calculation | chain gears | program

The presented paper deals with the design proposal and application of the program for calculation and check of chain gears. The computing program has been created as a spreadsheet in the working environment of the Microsoft Office program by the Excel application through defined sequences of the individual commands. The program serves for the design proposal of a chain drive by means of inserted databas (…)

UNDESIRABLE CONSEQUENCES OF INCREASED WATER TEMPERATURE IN DRINKING WATER DISTRIBUTION SYSTEM

Jana Novakova, Jan Rucka
Keywords: flushing | water quality | water temperature | water supply | drinking water distribution system | drinking water

The article is focused on the description of problems that can be caused by increased temperature of drinking water in public drinking water distribution system (DWDS). Increased water temperature is an actual issue that the water industry has had to address in recent years, particularly as a result of the ongoing climate change. In recent years, long periods with high air temperatures have been more fr (…)

CHANGE IN CONCEPT FROM CONVENTIONAL TO DIGITAL FACTORY OF THE FUTURE

Daniela Onofrejova, Dusan Simsik
Keywords: automated systems | industry 4.0 | production systems | digital production | digital factory

The study of the Digital Factory consists of the design of an automated manufacturing system with elements of autonomy within the concept of Industry 4.0. This study origin was inspired with the production of drumsticks. For the intended purposes, manufacturing system designs for Factories of Future are created. The system consists of elements that are part of the digital production with automated funct (…)

LASER SHOCK PEENING OF ALUMINIUM ALLOYS TO ENHANCE SURFACE PROPERTIES

Jan Kaufman, Marek Bohm, Jan Brajer, Sanin Zulic
Keywords: AA5083 | surface processing | cold working | residual stress | Laser Shock Peening

Laser Shock Peening (LSP) is a process where high energy nanosecond laser pulses are used to modify surface characteristics of treated materials. In this work, the LSP process is briefly explained and its effects on roughness, hardness and residual stresses of aluminium alloy 5083 are demonstrated. The LSP process is based on small plastic deformation caused by laser impacts on the surface which natural (…)

MODELING THE MELTING THRESHOLD OF MO FILMS UPON ULTRASHORT LASER IRRADIATION

Krystof Hlinomaz, Yoann Levy, Thibault Derrien, Nadezhda Bulgakova
Keywords: energy conservation | two-temperature model | melting threshold | thin film | ultrashort laser pulses

Modification of thin metallic films using ultrashort laser pulses involves interplay of numerous physical processes. Finding a right combination of laser parameters is essential for achieving the desired modification of a thin film deposited on a substrate. Numerical modeling is a convenient tool for gaining insights into ultrafast evolution of material properties and to predict an optimal range of irra (…)

SUPERHYDROPHOBIC STAINLESS STEEL SURFACE BY TWO-STEP NS LASER PROCESSING

Petr Hauschwitz, Radka Bicistova, Jagdheesh Radhakrishnan, Jan Brajer, Danijela Rostohar
Keywords: stainless steel | functional surfaces | superhydrophobicity | Laser micromachining

Growing demand for superhydrophobic surfaces in recent years is associated to many attractive science and engineering applications including self-cleaning, anti-icing and anti-corrosive behaviours. Stainless steel type AISI 316L is one of the most versatile and widely used engineering material in industries. Inspired by the “lotus effect” nano/microstructures has been fabricated by direct laser writing (…)

REVIEW OF SIPHONIC ROOF DRAINAGE SYSTEMS

David Fucik, Jan Rucka
Keywords: surface water | head of water | outlet | emergency drain | roof drain | siphonic drainage system

The article describes an introduction to the problem of drainage of flat roofs, namely by using a vacuum drainage system. The article describes the current state, which also describes the gravity drainage system, whose design is in partial "retreat", unless required by local conditions or the investor of the construction. The following describes the advantages and disadvantages of the vacuum system and (…)

INTENSITY DISTRIBUTION MODULATION OF MULTIPLE BEAM INTERFERENCE PATTERN

Dominika Jochcova, Jan Kaufman, Petr Hauschwitz, Jan Brajer, Jan Vanda
Keywords: laser microstructuring | Diffractive Optical Element | interference field simulation | multiple beam interference | Direct Laser Interference Patterning

Nanostructuring and microstructuring approaches frequently used in microelectronics manufacturing, such as electron beam lithography or nanoimprint lithography, are considerably slow. In order to reduce processing time, laser patterning methods based on interference of multiple beams have been developed. Within one laser pulse, a significant part of an irradiated area on a sample surface is patterned wi (…)

RESONANTLY ENHANCED FREQUENCY DOUBLING OF A CONTINUOUS-WAVE YTTERBIUM-DOPED FIBER LASER

Lukas Roskot, Martin Smrz, Ondrej Novak, Taisuke Miura
Keywords: periodically poled lithium niobate | enhancement cavity | frequency doubling | fiber laser

A single-mode ytterbium-doped continuous-wave fiber laser operated at a wavelength of 1030 nm is designed and utilized for frequency doubling at 515 nm in a periodically poled lithium niobate (PPLN) crystal. The standard single-pass of the PPLN results in a conversion efficiency of only 2 % due to the low intensity of the continuous-wave laser even though optimal focusing into the PPLN is used. Because (…)