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The content and binding of silver in galena
Němec, Matěj ; Goliáš, Viktor (advisor) ; Zachariáš, Jiří (referee)
Galena as the most important silverbearing ore is found in almost every Ag deposit. If the content of Ag is higher than 0,5 wt. % then is called galena solid solution - PbSss. The galena Ag has two forms of occurrence - inclusions and isomorphic silver. Aboat ninety percent of galena Ag is product of retrograde proces of PbSss cooling. These are matildite (AgBiS2), miargyrite (AgSbS2), diaforite (PbAg3Sb3S8), freislebenite (AgPbSbS3), pyrargyrite (Ag3SbS3) aramayoite (Ag(Sb,Bi)S2), freibergite (Ag12Sb4S13), gustavite (AgPbBi3S6) etc. The smaller amounth of isomorphic Ag is substituted as 2Ag+ = PbII+ . Under the usual conditions of deposition (200 - 300řC) , the solubility of Ag2S is to low. The content of Ag in galena under these conditions is not higher then 0,4 mol. % at 615řC. Most of the isomorphic Ag is bound in coupled substitution Ag+ + Bi III+ /Sb III+ = 2 PbII+ . In this case the content of Ag in PbS can be as high as 9 wt. % at 350 - 400řC. At the deposites where wasn't activated this Bi/Sb - Pb coupled substitution the content of Ag in galena is very low. The content of trace elements of Ag, Bi and Sb can also influence the galena crystal habit. Galena rich on Bi ususaly creates octahedral crystals. Galena with a higher content of Ag and Sb usualy creates cubic crystals.
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Physically Based Shading
Matěj, Šimon ; Lysek, Tomáš (referee) ; Starka, Tomáš (advisor)
This thesis deals with imaging of materials in computer graphics, using rendering methods based on physical properties of these materials. Physical principles of light propagation and its interactions with objects are analyzed, several rendering methods based on these principles are described and then analyzed for suitability in implementations. Some of these methods are demonstrated in application.
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Development and Programming of Low Power Cluster
Hradecký, Michal ; Nikl, Vojtěch (referee) ; Jaroš, Jiří (advisor)
This thesis deals with the building and programming of a low power cluster composed of Hardkernel Odroid XU4 kits based on ARM Cortex A15 and Cortex A7 chips. The goal was to design a simple cluster composed of multiple kits and run a set of benchmarks to analyze performance and power consumption. The test set consisted of HPL and Stream benchmarks and various tests for the MPI interface. The overall performance of the cluster composed of four kits in HPL benchmark was measured 23~GFLOP/s in double-precision. During this test, the cluster showed power efficiency about 0.58~GFLOP/W. The work also describes the installation of PBS Torque scheduler and HPC software build and installation framework EasyBuild on 32-bit ARM platform. The comparison with Anselm supercomputer showed that Odroid cluster is as effiecient as large supercomputer but with slightly higher price.
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Coherent optical communication systems
Štohl, Jakub ; Münster, Petr (referee) ; Kočí, Lukáš (advisor)
This bachelor thesis deals with the possibilities of coherent optical networks. Describes the elements of a coherent network. The practical part deals with the simulation of coherent optical networks using PM-QPSK and PM-16QAM modulation for bandwidth of 112 Gbit/s and 224 Gbit/s.
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