Actual number: 4/2020

ISSN 1339-5017 (Online)

Archive:


No. 2

MODELING AND PREDICTION OF RANDOM EVENTS IN MAINTENANCE, LOGISTICS, AND RISK ASSESSMENT

Author: Alena BREZNICKÁ, Alexej CHOVANEC

Abstract: Mathematical modeling and simulation is for an analysis, modeling and prediction of random events in operation, maintenance, logistics, and risk assessment very favorable, first of all for a possible visualization and monitoring through graphical outputs providing better perception and display of stochastic processes.

Keywords: risk, availability, maintenance, reliability

Vol. 11, 2017, No. 2, p. 1-5

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MODELING OF PROVIDING AVAILABILITY OF A MANUFACTURING LINE

Author: Alexej CHOVANEC, Alena BREZNICKÁ

Abstract: Designing of manufacturing working places supposes a draft of optimal number of machines to provide a planned daily production, or to create stand-by machines that could substitute a presupposed downtime in production caused by failures. In manufacturing systems demanding implementation of setting, maintenance and repairs of smaller range on manufacturing machines there is a need to determine an appropriate number of personnel carrying out maintenance. We use the most often the deterministic or stochastic methods of operational analysis to solve the mentioned problem. However they do not describe a time flow of failure rise eventually additional random effects in providing availability of complex systems in a real operation. Drafts of logistic and maintenance systems and modeling of availability of technical systems use more often connection of knowledge about operational reliability, economic and simulation modeling and they replace traditional approaches of process examination.

Keywords: manufacturing line, availability, maintenance

Vol. 11, 2017, No. 2, p. 6-12

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MODELING WITH TECNOMATIX PLANT SIMULATION

Author: Milan JUS

Abstract: The article was to present the possibilities and examples of using Tecnomatix Plant Simulation (by Siemens) to simulate the production process (increase production, eliminate idle time, etc.) and by applying simulated output in real manufactoring processes.

Keywords: modelling, simulation, computer simulation, Tecnomatix Plant Simulation

Vol. 11, 2017, No. 2, p. 12-15

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PHOTOVOLTAIC TRANSPORTABLE MEANS

Author: Ivan KOPECKÝ, Peter LIPTÁK

Abstract: Traditionally, sustainability has been framed in the three-pillar model: Economy, Ecology and Society are all considered to be interconnected and relevant for sustainability. This view subscribes to an understanding where a certain set of actions e.g. substitution of fossil fuels with renewably energy sources can fulfil all three development goals simultaneously. The relationship between renewable energy and sustainability involve both global and regional or local considerations. Implementation of renewable energy –based energy access programs is expanding quite rapidly, but research on the sustainability-related aspects is still quite limited. Photovoltaic (PV) materials and devices convert sunlight into electrical energy. A single PV device is known as a cell. An individual PV cell is usually small, typically producing about 1 or 2 watts of power. To boost the power output of PV cells, they are connected together in chains to form larger units known as modules or panels. Modules can be used individually, or several can be connected to form arrays. One or more arrays is then connected to the electrical grid as part of a complete PV system. Because of this modular structure, PV systems can be built to meet almost any electric power need, small or large.

Keywords: photovoltaic cell, PV systems, solar power

Vol. 11, 2017, No. 2, p. 16-19

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EFFECTS OF IRRADIATION ACCELERATED ELECTRONS ON SOME SELECTED MATERIALS FOR SPECIAL EQUIPMENT

Author: Peter LIPTÁK, Ivan KOPECKÝ

Abstract: The paper deals with possibilities in improving features of materials used for special equipment through irradiation by accelerated electrons. It relates with a possibility to improve mechanical features of ballistic materials used for a ballistic protection of an individual. At present time there are mainly materials of Kevlar type and ceramics. Their features, e.g. mechanical properties as well may change through irradiation of these materials with accelerated electrons. [1]. So in a practical application it would be possible to improve a ballistic protection of a bullet-proof vest as well as to decrease a weight of a vest meanwhile keeping the protection class.. The achieved results that are presented in the paper can be used also in other applications, e.g. protective clothes used in industry [2].

Keywords: irradiation of materials with accelerated electrons, ballistic protection of individual, mechanical features of materials, Kevlar, ceramics

Vol. 11, 2017, No. 2, p. 20-27

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SAFETY PRINCIPLES FOR STORAGE OF AMMUNITION AND EXPLOSIVES - PROTECTION OF STACKS AGAINST LIGHTNINGS

Author: Štefan Pivko

Abstract: All stack buildings and workplaces with ammunition and explosives must be equipped with lightning protection. Lightning rod is intended to protect the object from atmospheric discharges - lightning and its destructive effects. When lightning strikes the protected object, lightning rod conducts its safe discharge directly into the ground. The protection of stacks against lightings and their secondary effects must be carried out in accordance with STN EN 62305, which has replaced STN 341390.

Keywords: lightning rod, zone of protection, discharge, grounded conducting element

Vol. 11, 2017, No. 2, p. 28-30

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POSSIBLE REPLACEMENT OF SPECIAL STEELS IN HULL REPAIRS

Author: Danka RAKUSOVA

Abstract: Vessels, pontoons, armoured vehicles and much other special equipment had been produced from steels we do not have any more an access to. Budget restrictions limit a purchase of new ones. Sometimes we are able thanks to our capabilities to repair, restore or renovate them, sometimes we are allowed to do it through a licence. However, political and marketing barrier is so strong, that sometimes we have to spend huge investments only because of some small exchangeable or reparable parts. Availability of standards makes a decision about a new purchase easier. Even nowadays more information is available on internet; the manufacturers do not provide technological information if not related with a contract. Changes in property rights also hamper a process. Post production analysis of material is very demanding and needs special equipment to define a structure of steels having been used on a vessel structure. Quality of material on a hull of a vessel is crucial not only for passenger vessels, but also for vessels whose hull is stressed much more because of navigation conditions, such as ice breakers on river in winter time. Worn steel plates on a hull must be regularly checked and if needed replaced. However, quality of the steel plate being used must not be lower than a previous one. Paper provides some comparable marks of steels that could serve when replacing one mark for another one and in repairing procedures on a vessel hull.

Keywords: standards, quality, steel features, hull which express the principal topics of the paper

Vol. 11, 2017, No. 2, p. 31-35

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