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Element analysis of magnesium alloys using laser induced breakdown spectrometry
Veis, Samuel ; Fintová, Stanislava (referee) ; Doležal, Pavel (advisor)
Bachelor‘s thesis is aimed at assessing the possibilities of trace elements detection in magnesium alloys using laser induced breakdown spectroscopy with a focus on rare earth elements. Base materials were wrought magnesium alloy sheet ZE10 with thickness of 1,6 mm and ZE41 with thickness of 2 mm produced using Direct Chill casting method. Qualitative and quantitative ways of LIBS spectra evaluation were described in the work. Qualitative analysis confirmed the presence of La, Ce, Nd and Pr in ZE41, and La with Ce in ZE10. These informations confirm results of EDS analysis. For a demonstration, quantitative analysis of ZE10 was made, which confirmed the possibility of using LIBS for detection of REE in Mg alloys.
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Recycling modern cars
Borik, Matúš ; Charvát, Pavel (referee) ; Štětina, Josef (advisor)
Zem čelí nadmernému prekračovaniu recyklačných limitov organických a anorganických surovín, čo spôsobuje nedostatočnú absorpciu skleníkových plynov. Automobilový priemysel sa v posledných desaťročiach rapídne rozbehol a má na tom svoj podiel. Významný negatívny vplyv na rast výroby automobilov má ťažba zdrojov, ktorá prináša niekoľko environmentálnych problémov, ako je vyčerpanie zdrojov, neudržateľnosť životného prostredia, ktorá vedie ku globálnemu otepľovaniu, a zdravotné problémy spojené s ťažbou zdrojov a výrobou automobilov. Ak sa má udržať úroveň používania automobilov, hlavným riešením je zamerať sa na recykláciu a výrobu ekologických vozidiel. Výskum recyklačných metód moderných vozidiel a ich analýza je zameraním tejto bakalárskej práce, ktorej konkrétnym cieľom poskytnúť náhľad rôznych typov recyklačných postupov. Prvá časť sa zaoberá všeobecnými princípmi recyklácie a recykláciou vozidiel po častiach. Následne práca presúva svoju pozornosť na obnoviteľné zdroje a ich využitie v automobilovom priemysle (elektromobily) a recykláciu moderných automobilov vyradených z prevádzky. Posledná časť prináša bližší pohľad na možnosti skladovania energie z obnoviteľných zdrojov, špecificky na vodíka (H2), jeho využitie v palivových článkoch, recykláciu vodíkových automobilov a budúcnosť pohonu. Práca konzultovaná s expert inžinierom danej oblasti.
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Rare earth elements in electronic waste
Pospíšilová, Eliška ; Šebek, Ondřej (advisor) ; Strnad, Ladislav (referee)
Rare earth elements consist of 15 lanthanides, Y and Sc. They are currently very important materials in many industrial branches (metalurgy, pollishing). One of these options is the usage as the compound of phosphors in electronic devices (television and computer displays. Because of their manufacturing cost, options of recovery from waste electrical and electronic equipment (WEEE) are investigated. This thesis deals with compoud elements of phosphors from displays of type CRT (cathode ray tube) and plasma TV. The 37 samples of phosphors from different displays were taken and processed for study of the compoud elements. Phosphors were separated to 4 subgroups in accordance with the corresponding type of displays: black-and-white CRT television displays (CRT_CB), color CRT television displays (TV_B), color PC displays (PC_B) and monochromatic PC displays (PC_M). The study was carry out by multiple features analysis that combined the inductively coupled plasma mass spectrometry (ICP-MS), the inductively coupled plasma optical emission spectrometry (ICP-OES), the resistance furnace with infrared detector (RF-IF) and the atomic absorption spectrometry (AAS). Based on the results of this analysis, main elements and potentionally hazardous elements of phosphors subgroup were defined. Concentration of rare...
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China's rare earth monopoly: a study of the U.S. discourse
Lee, Chi Sin ; Riegl, Martin (advisor) ; Romancov, Michael (referee)
This thesis examines the way in which China's share of the rare earths global industry is constructed as a threat. The central argument of the research is that the US discourse presented a new form of danger through the lens of classical geopolitical thinking, thus, creating a new type of prospective conflict derived from resources that are perceived to be scarce and yet relatively abundant. It argues that the construction of this 'threat' that the US faces is a constant articulation of perceived vulnerabilities in shaping geopolitical identities and reinforcing ideologies through which are carried out by different actors. Rare earths are crucial for modern conditions and their applications include commercial, military and green technology but mining and production are neither economical nor environmentally friendly. The People's Republic of China is the principal exporter of these rare metals, but because of a territorial dispute in the South China Sea in 2010 it has been labelled as a monopoly power. This study seeks to examine the constructed threat that China poses to the US. China, here, is not only constructed to be a resource hungry giant but also a malicious state that would utilise its 'monopoly' status as geopolitical leverage. The thesis will employ discourse analysis and wisdoms of...
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China's rare earth monopoly: a study of the U.S. discourse
Lee, Chi Sin ; Riegl, Martin (advisor) ; Romancov, Michael (referee)
This thesis examines the way in which China's share of the rare earths global industry is constructed as a threat. The central argument of the research is that the US discourse presented a new form of danger through the lens of classical geopolitical thinking, thus, creating a new type of prospective conflict derived from resources that are perceived to be scarce and yet relatively abundant. It argues that the construction of this 'threat' that the US faces is a constant articulation of perceived vulnerabilities in shaping geopolitical identities and reinforcing ideologies through which are carried out by different actors. Rare earths are crucial for modern conditions and their applications include commercial, military and green technology but mining and production are neither economical nor environmentally friendly. The People's Republic of China is the principal exporter of these rare metals, but because of a territorial dispute in the South China Sea in 2010 it has been labelled as a monopoly power. This study seeks to examine the constructed threat that China poses to the US. China, here, is not only constructed to be a resource hungry giant but also a malicious state that would utilise its 'monopoly' status as geopolitical leverage. The thesis will employ discourse analysis and wisdoms of...
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Rare earth elements in electronic waste
Pospíšilová, Eliška ; Šebek, Ondřej (advisor) ; Strnad, Ladislav (referee)
Rare earth elements consist of 15 lanthanides, Y and Sc. They are currently very important materials in many industrial branches (metalurgy, pollishing). One of these options is the usage as the compound of phosphors in electronic devices (television and computer displays. Because of their manufacturing cost, options of recovery from waste electrical and electronic equipment (WEEE) are investigated. This thesis deals with compoud elements of phosphors from displays of type CRT (cathode ray tube) and plasma TV. The 37 samples of phosphors from different displays were taken and processed for study of the compoud elements. Phosphors were separated to 4 subgroups in accordance with the corresponding type of displays: black-and-white CRT television displays (CRT_CB), color CRT television displays (TV_B), color PC displays (PC_B) and monochromatic PC displays (PC_M). The study was carry out by multiple features analysis that combined the inductively coupled plasma mass spectrometry (ICP-MS), the inductively coupled plasma optical emission spectrometry (ICP-OES), the resistance furnace with infrared detector (RF-IF) and the atomic absorption spectrometry (AAS). Based on the results of this analysis, main elements and potentionally hazardous elements of phosphors subgroup were defined. Concentration of rare...
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Element analysis of magnesium alloys using laser induced breakdown spectrometry
Veis, Samuel ; Fintová, Stanislava (referee) ; Doležal, Pavel (advisor)
Bachelor‘s thesis is aimed at assessing the possibilities of trace elements detection in magnesium alloys using laser induced breakdown spectroscopy with a focus on rare earth elements. Base materials were wrought magnesium alloy sheet ZE10 with thickness of 1,6 mm and ZE41 with thickness of 2 mm produced using Direct Chill casting method. Qualitative and quantitative ways of LIBS spectra evaluation were described in the work. Qualitative analysis confirmed the presence of La, Ce, Nd and Pr in ZE41, and La with Ce in ZE10. These informations confirm results of EDS analysis. For a demonstration, quantitative analysis of ZE10 was made, which confirmed the possibility of using LIBS for detection of REE in Mg alloys.
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LPE Growth of III-V Semiconductors from rare-earth Treated Melts
Grym, Jan ; Procházková, Olga ; Zavadil, Jiří ; Žďánský, Karel
We focus on the characterization of InP and InGaAsP layers prepared by liquid phase epitaxy with rare-earth admixtures. We applied photoluminescence spectroscopy (PL), capacitance-voltage measurements, and secondary ion mass spectroscopy in order to explain: (i) the gettering effect and conductivity crossover of InP layers for Pr treated samples, (ii) narrowing of the PL and elecroluminescent spectra of the active InGaAsP region of a double-heterostructure LED.
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Physical properties of InP epitaxial layers prepared with dysprosium admixture
Grym, Jan ; Procházková, Olga
Physical properties of commonly prepared InP layers grown by LPE technique and those grown from Dy treated melt are compared. The layers were examined by SEM, low temperature PL spectroscopy, C-V measurements and temperature dependent Hall effect. Structural, electrical and optical properties of InP layers exhibit a significant dependence on the presence of Dy and its concentration in the melt. When increasing the concentration of Dy the reversal of electrical conductivity occurs.
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