National Repository of Grey Literature 63 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Gear design with tolerance analysis
Křivohlavý, Petr ; Křupka, Jiří (referee) ; Svoboda, Petr (advisor)
The thesis is concerned with tolerances of machine elements. The thesis explains dimensional and geometrical tolerance, surface texture and their interdependence. On the basis of the stated facts a simple technique is established to be followed when setting tolerance of machine elements. The procedure is further applied on the transmission that was selected from the three models on hand. The technique is focused mostly on shaft and gear tolerance. The thesis should provide the reader with understanding of how to tolerate selected machine elements.
Defect detection on fiber materials using machine learning
Lang, Matěj ; Richter, Miloslav (referee) ; Honec, Peter (advisor)
Cílem této diplomové práce je automatizace detekce vad ve vláknitých materiálech. Firma SILON se již přes padesát let zabývá výrobou jemné vaty z recyklovaných PET lahví. Tato vata se následně používá ve stavebnictví, automobilovém průmyslu, ale nejčastěji v dámských hygienických potřebách a dětských plenách. Cílem firmy je produkovat co nejkvalitnější výrobek a proto je každá dávka testována v laboratoři s několika přísnými kritérii. Jednám z testů je i množství vadných vláken, jako jsou zacuchané smotky vláken, nebo nevydloužená vlákna, která jsou tvrdá a snadno se lámou. Navrhovaný systém sestává ze snímací lavice fungující jako scanner, která nasnímá vzorek vláken, který byl vložen mezi dvě skleněné desky. Byla provedena série testů s různým osvětlením, která ověřovala vlastnosti Rhodaminu, který se používá právě na rozlišení defektů od ostatních vláken. Tyto defekty mají zpravidla jinou molekulární strukturu, na kterou se barvivo chytá lépe. Protože je Rhodamin fluorescenční barvivo, je možné ho například pod UV světlem snáze rozeznat. Tento postup je využíván při manuální detekci. Při snímání kamerou je možno si vypomoci filtrem na kameře, který odfiltruje excitační světlo a propustí pouze světlo vyzářené Rhodaminem. Součástí výroby skeneru byla i tvorba ovládacího programu. Byla vytvořena vlastní knihovna pro ovládání motoru a byla upravena knihovna pro kameru. Oba systém pak bylo možno ovládat pomocí jednotného GUI, které zajišťovalo pořizování snímku celé desky. Pomocí skeneru byla nasnímána řada snímků, které bylo třeba anotovat, aby bylo možné naučit počítač rozlišovat defekty. Anotace proběhla na pixelové úrovni; každý defekt byl označen v grafickém editoru ve speciální vrstvě. Pro rozlišování byla použita umělá neuronová síť, která funguje na principu konvolucí. Tento typ sítě je navíc plně konvoluční, takže výstupem sítě je obraz, který by měl označit na tom původním vadné pixely. Výsledky naučené sítě jsou v práci prezentovány a diskutovány. Síť byla schopna se naučit rozeznávat většinu defektů a spolehlivě je umí rozeznat a segmentovat. Potíže má v současné době s detekcí rozmazaných defektů na krajích zorného pole a s defekty, jejichž hranice není tolik zřetelná na vstupních obrazech. Nutno zmínit, že zákazník má zájem o kompletní řešení scanneru i s detekčním softwarem a vývoj tohoto zařízení bude pokračovat i po závěru této diplomové práce.
Studium vedení tepla metodami počítačového modelování
STANĚK, Jakub
This diploma thesis is concerned with a problem of the line heat simulation by different kinds of materials with computer - aided COMSOL Multiphysics. The thesis is composed of three thematic units. In the first part there is a line heat principle shortly described and his basic physical quantities which are necessary for correct defining of the simulation. The second part is concerned with the software, its function, auxiliary modulus and a description of single actions, which are essential for making of the model. In the last part there is the whole process of the multiphysical task creation that enables to simulate line heat in a specific material in reliance on time.
A Project for the production of the transmission case for the winch
Hrbáček, Emil ; Strejček, Jan (referee) ; Kalivoda, Milan (advisor)
The project elaborated within engineering studies. The project is submitting design of technology production of precise holes for rolling bearings which are located in transmission case for the winch. Variants of production technologies were designed based on the construction drawings of transmission case. Chosen type of technology is boring. Boring was performed on the CNC machine DMF 180 produced by DMG MORI. DMF 180 allows precise production of bearings holes. Via selected criteria, it was selected the better variant of two. The criteria were: cylindricality, cohesiveness, position of elements and surface quality.
Design of gearbox for electric motorcycle
Novotný, Tomáš ; Prokop, Aleš (referee) ; Svída, David (advisor)
The aim of the thesis is a summarization of current state of knowledge of motorcycle clutches and transmissions and subsequent design of clutch and transmission for electric powered motorcycle. The main topic is design of the clutch of which components were processed by stress analysis and designed for fatigue safety. On top of that, the thesis deals with the design of primary transmission and gear ratios.
Test Rig Design Proposal for the Experimental Validation of Transmission Parameters in Closed Loop Torque Condition
Otipka, Václav ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
The thesis deals with the design of the experimental testing rig. Test rig is designed to measure NVH transmission parameters. First, basic knowledge of vibro-acoustic measurement is discussed. This is followed by an evaluation of the most commonly used power devices to derive real loads on measured gearboxes. In more detail, a back-to-back test rig is disassembled among other things. In the thesis are described two main components, which are composed of a connecting element and a test bench. Both components were optimized during the design due to their modal properties. Numerical modal analysis was performed in ANSYS Workbench software. The thesis also includes strength calculations performed using both numerical and analytical approaches. The indispensable result of the design work is the complete drawing documentation. Finally, measurements of vibrations and noise on the physically made connecting element assembly have been performed and subsequently evaluated.
Computational Models of Transmission Dynamics
Czakó, Alexander ; Řehák, Kamil (referee) ; Prokop, Aleš (advisor)
This bachelor thesis deals with a summary of knowledge about the computational models of transmission dynamics. Dynamics modelling has different levels of complexity. From the modal, harmonic analysis solved in the FEM, up to creating a virtual prototype in the MBS softwares. In the introduction, there are presented the basics of analytical dynamics and mechanical oscillation which are the basis of individual analysis. Vibration sources in transmission are described as well.
Measure the impact of wireless technologies on TEM
Prokop, Martin ; Čudek, Pavel (referee) ; Polsterová, Helena (advisor)
The purpose of this diploma thesis is to research and compare available wireless communication technologies (frequency, modulation type, transmission speed and consumption). Describe transmission electron microscopes theory and deduce the most sensitive microscope parts to high frequency distortion. Investigate effect of wireless technology on CE standards and come up with, perform and evaluate the influence measurement of chosen technologies on base parameters of transmission electron microscope.
Free living amoebae as causative agents of human infections.
Markovičová, Ivana ; Nohýnková, Eva (advisor) ; Doležal, Pavel (referee)
Free living amoebae as causative agents of human infections are world wide occuring organisms with the ability of dual lifestyle both in nature, which is their original habitat, so within host tissue. The aim of this theses is to summarize the basic available knowledge of the pathogenic species Naegleria fowleri and Balamuthia mandrillaris and of the pathogenic genus Acanthamoeba which invade CNS and are causative agents of rare but serious human infections, often leading to death of a patient. The exception of their deathly consequences is an Acanthamoeba keratitis infection in which non curing cases lead to a significant visual impairment and even to visual loss. In each of the chapters, the work is tend to summarize transmision ability, mechanisms of pathogenesis and pathophysiology of these three free living amoebae in order to describe their ability to cause infection.
Characterization of eukaryotic translation initiation factor 3 subunits (eIF3) in A. thaliana male gametophyte
Linhart, Filip ; Hafidh, Said (advisor) ; Retzer, Katarzyna (referee)
From RNA-to-protein, translation initiation and protein synthesis is mediated by trans-acting factors that recognize mRNA features common to almost all eukaryotes. Eukaryotic translation initiation factor 3 complex (eIF3) is a highly conserved protein complex that recognizes 5'-CAP elements of the mRNA to initiate translation. eIF3 consists of nine subunits, three of them having two isoforms: eIF3A, eIF2B1, eIF3B2, eIF3C1, eIF3C2, eIF3D, eIF3E, eIF3F, eIF3G1, eIF3G2, eIF3H and eIF3K. This work deals with functional characterization, expression and subcellular localization of eIF3B1, eIF3B2 and eIF3E in Arabidopsis thaliana male gametophyte and interaction of eIF3E with the Constitutive photomorphogenesis 9 (COP9) complex as a regulatory complex of eIF3E post-translational control. Here we show that depletion of eif3b1 or eif3b2 is not gametophytic lethal and that the two protein might function redundantly, whereas, knockout of eIF3E causes male gametophyte lethality. Interestingly, eif3b1 show post-fertilization defects during embryogenesis, suggesting that its redundancy with eIF3B2 is restricted to the gametophyte. Gene expression studies revealed high expression of eIF3 subunits in actively dividing zones of leaf primordia, root meristem and root elongation zones as well as in the vegetative...

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