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Possibilities of enhancement of kaolin whiteness by separation of components containing titanium
Vaculík, Josef ; Švec, Jiří (referee) ; Opravil, Tomáš (advisor)
Theme of the bachelor’s thesis is enhancement of kaolin whiteness primarily by removing titanium and iron. Titanium itself in the modification of anatase doesn’t decrease whiteness, more likely is the other way around. Unwanted modification is rutile, which is dark and it decreases substantially the whiteness of kaolin. The most significant impact on whiteness of kaolin has the iron (III) compounds that are usually contained with titanium in minor minerals in kaolin’s raw material. Main goal of thesis was to test the hydrothermal conditions on separation of parts containing titanium and iron from the kaolin’s material. Separation in the hydrothermal condition was performed by infusing kaolin in the solutions of acids of various concentrations. To find out the final whiteness of kaolin material after hydrothermal treatment was used UV-VIS method with reflective module and to find out the amount of iron and titan transferred to the solution of acids because of hydrothermal treatment was used ICP-OES method.
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Kidnapping Otherness. Tourism, Imaginaries and Rumor in Eastern Indonesia
Kábová, Adriana ; Halbich, Marek (advisor) ; Vrhel, František (referee) ; Knotková - Čapková, Blanka (referee)
This dissertation is based on my research into distinction processes (Calhoun, 1994; Cerulo 1997) between tourists and inhabitants of West Sumba in Eastern Indonesia. The imaginiaries (Castoriadis, 1987; Strauss, 2006; Lacan, 1977; Anderson, 1991; Salazar, 2012) of West Sumbanese people about foreigners also emerge from diving rumors (Bysow, 1928; Allport and Postman, 1947/1965). Their origins, dissemination, and sharpening processes, as well as their consequences will be analysed herein. This case study demonstrates how mental models of otherness are formed and reified, how they clash, and for what purposes they may be utilized. It will also analyze how imaginaries influence behavior and may lead to miscommunication in West Sumba.
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Possibilities of enhancement of kaolin whiteness by separation of components containing titanium
Vaculík, Josef ; Švec, Jiří (referee) ; Opravil, Tomáš (advisor)
Theme of the bachelor’s thesis is enhancement of kaolin whiteness primarily by removing titanium and iron. Titanium itself in the modification of anatase doesn’t decrease whiteness, more likely is the other way around. Unwanted modification is rutile, which is dark and it decreases substantially the whiteness of kaolin. The most significant impact on whiteness of kaolin has the iron (III) compounds that are usually contained with titanium in minor minerals in kaolin’s raw material. Main goal of thesis was to test the hydrothermal conditions on separation of parts containing titanium and iron from the kaolin’s material. Separation in the hydrothermal condition was performed by infusing kaolin in the solutions of acids of various concentrations. To find out the final whiteness of kaolin material after hydrothermal treatment was used UV-VIS method with reflective module and to find out the amount of iron and titan transferred to the solution of acids because of hydrothermal treatment was used ICP-OES method.
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Spektrální distribuce použitých světelných zdrojů a hodnota bělosti FWA vzorků
Vik, Michal ; Viková, Martina ; Prince Periyasamy, Aravin
The Whiteness of textiles, plastics, paper and paints is important aspects, which are considered in daily life. Customers usually prefer white products, especially in summer because of comfort reasons. In addition, white, being an achromatic color has a physiological effect on human sensation. Generally, High whiteness is not possible to get through only bleaching process. Therefore, the application of FWA’s (Fluorescence Whitening Agents) is a common practice in industry where the need to achieve “high” whiteness. In the case of white materials, the nature of these chemicals is to absorb light in the invisible, or near ultra-violet, region of the spectrum and then re-emit this light as fluorescence in the visible region of the spectrum. This re-emitted light generally occurs between 420-500nm. The effect is a greater degree of reflectance in the blue region of the spectrum, therefore a “bluer” white. In effect, this process produced much whiter whites! Consequently to other color attributes of an object depends on many factors, such as lighting (illumination), size of sample, and background and surrounding colors. Much more importantly, color is a subjective phenomenon and depends on the observer. In this article were discussed the influence of SPD (Spectral Power Distribution) tested light sources on whiteness. Solid-state lighting (white LEDs, etc.) is necessary to improve by a full-visible-spectrum technology because standard white LEDs are unable to activate FWA’s sufficiently. Ra does not capture this issue or other conventional color rendition metrics, although it corresponds to a very large color distortion for shades of white. Full-visible-spectrum LEDs emit no harmful ultra-violet light, but enough violet light to properly excite FWA’s and render whites like natural sources.
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