Spelling suggestions: "subject:"akustik""
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Hodnocení kvality svarů heterogenních materiálů pomocí akustické emiseHafner, Josef January 2017 (has links)
This thesis is focused on the evaluation of hetereogeneous weld joints made by CMT technology using acoustic emission. The thesis is divided into four parts. The first one is focused on the describe CMT technology. The second part describe the principle of acoustic emission. The following part includes the methodology of experimental part. The final section deals with on the relation between the tensile strength of the samples with the measured values of acoustic emissions from the welding and cooling of the material.
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Monitoring degradačních vlastností karbonuNěmeček, Václav January 2017 (has links)
In the diploma thesis there was made an attempt to compare the samples of carbon fiber composite materials (carbon). The teoretical part presents knowledge of the composition of composite material. Next, there is described the production and possible use of carbon composite materials in various technological branches. In the practical part the thesis focuses on the testing of composite materials made of carbon fiber with different orientation and weights of fibers. There is performed a tensile test and simultaneous monitoring of the course of the tensile test by acoustic emission. Finally, the statistical processing of the measured values occurs.
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Akustická diagnostika strojů / Acoustic diagnostics of machinesGajdoš, Petr January 2012 (has links)
The aim of this master´s thesis is to work out a comparison and evaluation of selected methods used for sound field mapping. Thesis will include software tools and results of sample measurement on test object for each mapping method.
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Akustická komunikace a její variabilita u vybraných populací syslů rodu Spermophilus. / Acoustic communication and its variability in selected populations of ground squirrels of the genus SpermophilusSchneiderová, Irena January 2012 (has links)
The thesis deals with vocalizations produced by Eurasian ground squirrels of the genus Spermophilus. It is mainly focused on inter-species and intra-species variability in acoustic structure of alarm calls which are emitted in presence of predators.The major part of the thesis deals with intra-species variability in acoustic structure of the alarm calls in five Eurasian ground squirrels, Spermophilus citellus, S. taurensis, S. xanthoprymnus, S. suslicus and S. fulvus. It has been confirmed that the alarm calls of these ground squirrels show a high level of species specificity. The thesis further describes another vocalizations produced by three Eurasian ground squirrel species, Spermophilus suslicus, S. citellus and S. fulvus, and shows that with the exception of the alarm calls, vocal repertoires of these three ground squirrels are remarkably similar. The last part of the thesis deals with individual distinctiveness of the alarm calls of three Eurasian ground squirrels, Spermophilus citellus, S. taurensis and S. xanthoprymnus. It has been shown that the alarm calls of these species have a significant potential to encode information about caller identity.
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Fyzikální a mechanické vlastnosti nových slitin na bázi Mg, vliv příměsí / Influence of Solid Solution Elements and Precipitate Formation on the Mechanical Behaviour of Magnesium AlloysIllková, Kseniya January 2013 (has links)
Title: Influence of Solid Solution Elements and Precipitate Formation on the Mechanical Behaviour of Magnesium Alloys Author: Mgr. Kseniya ILLKOVÁ Department / Institute: Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University in Prague Supervisor of the doctoral thesis: Doc.RNDr.František Chmelík, CSc. Department of Physics of Materials, Faculty of Mathematics and Physics, Charles University in Prague Abstract: Mg-1 wt. % Mn alloys containing about 1 wt.% of calcium (MX10), aluminium (AM11), cerium(ME11), yttrium (MW11), neodymium (MN11) and 8 wt.% of aluminium (AM81) were indirectly extruded with two different speeds. The partially recrystallised microstructures obtained in MX10, AM11, ME11 and MW11 after slow extrusion exhibited bimodal grain size distributions. Only in the case of AM81 and MN11 a fully recrystallised microstructure was found, indicating differences in the grain nucleation rate during recrystallisation. In these alloys, the weakest texture and, correspondingly, the lowest asymmetry in mechanical properties were also observed. The acoustic emission technique was used to reveal dislocation or twin controlled deformation in differently textured fractions of the microstructure during tensile and compression testing. A direct correlation between the acoustic...
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Vliv variability stavby rezonančního dřeva na jeho akustické vlastnostiSchwarzer, Martin January 2014 (has links)
This work was the structure of resonant spruce wood devoted to. The tree-ring widths and summer wood measure were measured. By use of non - destructive methods their acoustic properties were measured - speed of sound, acoustic constant, logarithmic decrement of damping, acoustic wave resistance, wood - density and Young's modulus. Data were statistically analyzed and the wood structure coefficient of variation for each specimen was calculated. There were three different methodologies for verification of the wood structure variability effect formulated. Subsequently, it was found that it is possible to determine the effect on the acoustic properties of the wood macroscopic structure variability.
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Past pro studium rozptylu světla na prachových zrnech / Dust trap for light scattering studyBartoň, Petr January 2017 (has links)
Title: Dust trap for light scattering study Author: Petr Bartoň Department: Department of Surface and Plasma Science Supervisor: doc. RNDr. Jiří Pavlů, Ph.D., Department of Surface and Plasma Science Abstract: Light scattering on small grains is common interaction occurring wi- dely in space environments, including Moon surface, dusty nebulas or even the upper atmosphere of the Earth. For experimental measurements of light scatte- ring intensity profiles, we designed and constructed a unique experiment. Using so called acoustic trapping, we are able to capture a single dust grain (or small water droplet) in midair, to irradiate it with the laser beam, and to observe scattered light directly with the photodiode mounted on a precise goniometer. In the thesis, we present not only construction details, but also the first results, which help us to evaluate abilities of the experiment, and provide useful recommendations for further development of all dust-related experiments. Keywords: light scattering, acoustic trap, dust grain, scattering measurement 1
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Principy stanovení hladiny akustického výkonu / Sound power level estimation principlesFajt, Jakub January 2017 (has links)
This Master´s thesis deals with principles of determination of the sound power level. At the very beginning there is an explanation of important concepts. Afterwards there is an overview of standards that deal with the sound power level determination, including the ČSN EN ISO 9614-1 standard which is used for the experiment. Last but not least, there is described the experiment, consisting of several measurements of the same object, but every time with different configuration of measuring and sound reflective surfaces.
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Lokalizace a identifikace typu poškození pneumatických pohonů / Localization and identification of damage type of pneumatic drivesRichter, Vladislav January 2018 (has links)
Pneumatic drives are an integral part of many machinery, with high demands on their reliability. Unfortunately, they sometimes fail, either due to improper production or assembly at the factory or by gradual degradation of moving parts and sealing elements during operation. Current diagnostic methods do not allow localization or identification of the type of damage and do not allow the operator to make a qualified decision. This work deals with the use of acoustic emission for these purposes. On PB type cylinders manufactured by Poličské strojírny a.s., a methodology is introduced which leads to the direct identification or at least localization of selected defects. By implementing this methodology in the final inspection of the production plant, the percentage of exposed pieces of waste will be increased, thus preventing accidents of these faulty pieces during operation.
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Využití akustické emise pro monitorování leteckých konstrukcí / Using Acoustic Emission for aircraft structure monitoringKrasavin, Taras January 2019 (has links)
This thesis deals with the theoretical and practical part of the phenomenon of acoustic emission. The thesis examined the theoretical foundations of this phenomenon and also described the equipment that was used in the laboratory of VUT in Brno to perform measurements. Then measurements and their analysis were described. Several possible errors that occurred during the work on the thesis were also described. Error description is the basis for error-free laboratory testing and for improving the quality of laboratory testing.
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