Quantitive optical analysis using cell phone

Tato bakalářská práce pojednává o metodách kvantitativní kolorimetrické analýzy s využitím mobilního telefonu a návrhu vlastního analyzátoru. Teoretická část se věnuje základním vlastnostem světla a rozdělení optické spektrální analýzy, jež je popsána několika optickými metodami. Dále je zmíněno rozdělení kolorimetrických analyzátorů podle jejich typů. Důležitou složkou je zaměření na kolorimetrickou analýzu s využitím mobilního telefonu a obeznámení se s možnostmi analýzy tekutin a pevných vzorků. Praktická část se věnuje návrhu samostatného analyzátoru s využitím mobilního telefonu, vyvinuté aplikaci zahrnující možnost kalibrace hodnot připravených vzorků a následnému hodnocení koncentrace iontů v neznámém vzorku. Pro přesnost výsledků je zhotoven světlotěsný temný kryt na 3D tiskárně.This bachelor‘s thesis discusses methods for the quantitative colorimetric analysis using a cell phone and a design of my own analyzer. Theoretical part deals with basic characteristics of light and division of optical spectral analysis, which is described by several optical methods. The bachelor’s thesis also contains the division of colorimetric analyzers according to their types. The most important part is focused on a colorimetric analysis using the cell phone and familiar with the possibilities of analysis of liquids and solid samples. The practical part deals with the design of a separate analyzer using the cell phone, developed application including the possibility of calibration values of prepared samples and subsequent evaluation of ion concentration in unknown sample. For the accuracy of the results is made dark light-tight cover printed by 3D printer.

Metallurgical preparation of Nb-Al and W-Al intermetallic compounds and characterization of their microstructure and phase transformations by DTA technique

The possibilities of metallurgical preparation of 40Nb-60Al and 15W-85Al intermetallic compounds (in at.%) by plasma arc melting (PAM) and vacuum induction melting (VIM) were studied. Both methods allow easy preparation of Nb-Al alloys; however, significant evaporation of Al was observed during the melting, which affected the resulting chemical composition. The preparation of W-Al alloys was more problematic because there was no complete re-melting of W during PAM and VIM. However, the combination of PAM and VIM allowed the preparation of W-Al alloy without any non-melted parts. The microstructure of Nb-Al alloys consisted of Nb2Al and NbAl3 intermetallic phases, and W-Al alloys consisted mainly of needle-like WAl4 intermetallic phase and Al matrix. The effects of melting conditions on chemical composition, homogeneity, and microstructure were determined. Differential thermal analysis was used to determine melting and phase transformation temperatures of the prepared alloys.Web of Science258art. no. 200

Hydrometalurgical processing of printed curciut boards

Import 14/08/2008Prezenční637 - Katedra neželezných kovů,rafinace a recyklaceNeuveden

Rozbor vad odlitků automobilových kol ze slitin hliníku

Import 18/10/2006Prezenční632 - Katedra slévárenstv

Phase transition temperatures of Sn-Zn-Al system and their comparison with calculated phase diagrams

The Sn–Zn–Al system was studied in connection with the possible substitution of lead-based solders for temperatures up to 350 °C. Ternary alloys with up to 3 wt% of aluminium were prepared. The investigated alloys lie close to the monovariant line (eutectic valley) of the Sn–Zn–Al system. The temperatures of phase transitions of six binary Sn–Zn reference alloys and fourteen ternary Sn–Zn–Al alloys using DTA method were investigated in this paper. DTA experiments were performed at the heating/cooling rate of 4 °C min−1 using Setaram SETSYS 18TM experimental equipment. The temperatures of phase transitions in the ternary Sn–Zn–Al system were obtained, namely, the temperature of ternary eutectic reaction T E1 (197.7 ± 0.7 °C), temperature of ternary transition reaction T U1 (278.6 ± 0.7 °C), temperatures of liquidus and other transition temperatures for studied alloys. Temperatures obtained during DTA heating runs were used as authoritative. DTA curves obtained during cooling enabled realising better differentiation of the obtained overlapped heat effects (peaks) during heating. Theoretical isopleths of the Sn–Zn–Al phase diagram were calculated using the Thermocalc software and MP0602 thermodynamic database. Experimental data were compared with the calculated temperatures, and a good agreement was obtained.Web of Science110137836

Preparation and properties of master alloys Nb-Al and Ta-Al for melting and casting of g-TiAl intermetallics

The advantages of gamma TiAl-based alloys including their specific modulus, specific high-temperature strength and oxidation resistance make them attractive candidates as high-temperature structural materials in the automotive, aerospace and power industries. Currently most attention is paid to the alloys of the third and fourth generations. However, this type of alloys contains relatively high amounts of refractory metals such as Nb and Ta. The high melting points of these metals (2477 and 3017) °C are problematic for the preparation of these products with the conventional casting, because it is necessary to use higher temperatures and thus, generally, longer total melting times. This may result in increased oxygen amounts in the products and in decreased mechanical properties. The use of Nb-Al and Ta-Al master alloys for the preparation of the resulting Ti-Al-Nb and Ti-Al-Ta alloys is highly suitable because of the reduction in the temperature during melting. This article describes the preparation of selected master alloys Nb-60Al and Ta-80Al (x/%) with the melting points of about 1600–1650 °C using plasma melting. The optimum conditions for the preparation of these master alloys (current density, feed speed, distribution and size of charge) were characterised in order to maximise the purity and homogeneity. The prepared alloys were studied with light microscopy (LM), backscattered scanning electron microscopy (BSE), energy-dispersive spectrometry (EDS), and the melting temperature was evaluated with a differential thermal analysis (DTA).Web of Science491302