Žilinská univerzita v Žiline

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    Vplyv teploty na Barkhausenov šum v Co a Gd
    (University of Žilina, 2024) Neslušan, Miroslav; Čížek, Jakub; Mičietová, Anna; Čilliková, Mária
    The present paper deals with Barkhausen noise emission in Gd. Barkhausen noise emission was investigated in the temperature range mainly below the Gd Curie temperature when the spontaneous magnetization in Gd occurs. Barkhausen noise from the heavy rare-earth Gd is compared with Barkhausen noise emission from the transition metal Co measured at the same magnetizing and other conditions. This study demonstrates that Barkhausen noise emitted from Gd is much weaker than that originating from Co. This is a consequence of different spin exchange interaction among the neighbouring atoms, domain wall thickness as a well as domain wall energies. Moreover, Barkhausen noise is temperature sensitive especially for Gd sample as a result of the altering magneto-crystalline anisotropy.
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    Vplyv striedavého namáhania na zmenu teploty vzduchu v pružnom pneumatickom elemente
    (University of Žilina, 2024) Krajňák, Jozef; Maláková, Silvia; Kepeň Harachová, Daniela
    Rubber as a material is one of the frequently used materials in mechanical engineering. This article deals with rubber, or flexible pneumatic elements, the main part of which is rubber. We determine the effect of alternating stress on the temperature change in the flexible pneumatic element under this variable load. We describe a device that serves this purpose. This device was designed and manufactured in our department. We also determine the effect of the air pressure of the flexible element on the temperature of the air and the temperature of the flexible elements. We need to find out the magnitude of these temperatures so that we can determine whether these flexible elements can work without significant negative changes in physical properties.
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    Vplyv vysokej prevádzkovej teploty na funkčnosť ložísk
    (University of Žilina, 2023) Kantoríková, Elena
    Rolling bearings are among the most important parts of machines and equipment. Many malfunctions in operation can be prevented by the correct choice of bearing, regular inspection and maintenance. The failure rate of the bearing is affected by many factors such as inappropriate storage, incorrect assembly, intrusion of foreign particles into the bearing spaces, inappropriately selected lubricant, or incorrect handling, transportation, etc. If damage or other deficiencies occur in rolling bearings, it is important to determine the cause of the damage so that appropriate measures can be taken to prevent their recurrence. Incipient damage to the bearing is reflected in the operation of the bearing, usually by a rise in temperature, or an increase in noise and stronger vibrations.
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    THE IMPACT OF TEMPERATURE AND WEAR ON LI-PO ACCUMULATORS DISCHARGE CHARACTERISTICS
    (Žilinská univerzita v Žiline, 2020) Kubáč, Tomáš; Hospodka, Jakub
    The goal of this paper was to find out how the ambient temperature affects the discharge characteristics and the useful energy density of lithium polymer accumulators. Also, to identify how these parameters are affected by age and wear of these accumulators. Li-Po accumulators are the most used energy source for small unmanned aerial vehicles. It is very important to know limitations of this energy source to allow efficient and safe usage. Especially these days, when these machines are being introduced into many industries. It has been found that low temperatures have a negative impact on the available accumulator capacity, especially the older ones. High temperatures, on the other hand, only slightly increased the capacity of the new accumulator. The old accumulator was affected more, higher temperatures helped to increase its available capacity. Using information gathered form this paper would help them use Li-Po accumulators more efficiently and save money on new ones because of increased life time.
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    TBC VRSTVY A ICH VPLYV NA ZVYŠOVANIE TEPELNEJ ODOLNOSTI MATERIÁLOV
    (Žilinská univerzita v Žiline, 2020) Novakov, Mário; Čerňan, Jozef
    Paper is dedicated to TBC protective elements, which are used to increase heat resistance of materials used in aircraft turbine engines. In individual sections are described in detail methods of protection and increase in heat resistance using TBC materials further described in the paper. Protective elements are applied to combustion chamber and the assembly behind it – turbine and exhaust nozzle of the jet engine. Paper is dedicated to general theory of turbine engine parts, TBC layers and final experiment. Significance of these TBC layers and comparison of the same material with and without TBC layer will be aim of the experiment with thermal camera and gas burner which will simulate environment of combustion chamber.