Waste is one of the biggest problems in every European country. Formation of waste reveals technological level of a country and creates costs to a society from the economical and ecological point of view. In Europe waste is usually collected and loaded in dumps. Recently, amounts of waste burning are increasing. The effects of waste burning and dumps are obvious: during burning the pollution spreads to an environment, affecting global climate warming; also extremely toxic pollutants (dioxins and furans) and their volatile derivatives form. At present the major part of waste in Lithuania is taken to dumps. Most of dumps in the country do not satisfy even the environmental and sanitary-hygienic requirements. Stiffening the ecological requirements, applying directives of European Union, most dumps will be closed. The waste at the moment ending in dumps may be processed and recycled in future. The integrated application of local raw materials together with various wastes may solve many environmental problems in Lithuania and may affect positively the European ecological balance. To investigate the possibilities to apply the waste, causing the most problems in our country, to the production of building ceramics made of local easily fusible hydro-micous clays. To determine the most optimal quantities of additives such as oil industry waste (used catalyst of GP534 grade, Russia) and shredded rubber of auto tyres, to select the most suitable burning regimes, to analyse the... [to full text]

Disertacijoje yra nagrinėjama, kokią įtaką ličio katijonų ir deguonies vakansijų (Vo) kietųjų elektrolitų elektrinėms savybėms daro jų struktūra ir elementinė sudėtis. Darbe yra aprašomos technologinės superjoninių junginių (SJ) keramikų ir sluoksnių gamybos sąlygos, lemiančios jų mikrostruktūrą, bei pateikiami SJ paviršių, temperatūrinio stabilumo ir elektrinių savybių tyrimo rezultatai. Li+ SJ priklauso monoklininei, ortorombinei arba romboedrinei singonijoms. Keramikų mikrostruktūra labiausiai priklauso nuo jų kepinimo temperatūros. LiCe2/3PO4 keramiką paveikus elektriniu lauku, XPS buvo parodyta, kad šioje medžiagoje vyksta Li+ jonų pernaša. Kompleksinės varžos spektroskopijos tyrimai parodė, kad sistemose Li1+xScxZr2-x(PO4)3, Li1+xZr2-2xAlxTix(PO4)3 ir Li1+xGe2-2xAlxTix(PO4)3 (čia x = 0,1, 0,2, 0,3), didinant x, didėja kristalitiniai keramikų laidžiai, o jų aktyvacijos energijos mažėja. Li3Sc2–xBx(PO4)3 junginiuose vykstančio superjoninio fazinio virsmo temperatūra priklauso nuo x. Li3-xSc2-x-yYyZrx(PO4)3 sistemoje kai x = 0,1, y = 0, 0,1 temperatūrinėse kristalitinio laidžio prieklausose yra stebimos anomalijos, susijusios su superjoniniais faziniais virsmais šiose medžiagose, o kai x = 0,2 tirtame temperatūrų intervale faziniai virsmai nevyksta. Magnetroninio dulkinimo metodu suformuotų YSZ storųjų sluoksnių joninis laidis ir šio laidžio aktyvacijos energija priklauso nuo jų paruošimo technologinių sąlygų. Didinant NiO-CGO sluoksnių, suformuotų purškimo pirolizės... [toliau žr. visą tekstą] / The influence of the structure and elemental composition of lithium ions’ and oxygen vacancies’ (Vo) solid electrolytes (SE) on their electrical properties are investigated in the dissertation. The technological conditions of SE ceramics’ and films’ fabrication, which influence their microstructure, are described. The results of the investigation of the surfaces, temperature stability, and electrical properties are presented. Li+ SE belong to monoclinic, orthorhombic, or rhombohedral symmetries. The microstructure of the ceramics is mainly influenced by the temperature of their sintering. It has been shown by XPS that LiCe2/3PO4 ceramic is Li+-ion conductor. Complex impedance spectroscopy investigation showed that the increase of x in the systems Li1+xScxZr2-x(PO4)3, Li1+xZr2-2xAlxTix(PO4)3, and Li1+xGe2-2xAlxTix(PO4)3 (where x = 0.1, 0.2, 0.3) leads to the increase of bulk ionic conductivity of the ceramics and to the decrease of its activation energy. Phase transition temperature in Li3Sc2–xBx(PO4)3 compounds depends on x. The anomalies of temperature dependencies of bulk conductivity of Li3-xSc2-x-yYyZrx(PO4)3 system were observed when x = 0.1, y = 0, 0.1. The anomalies are related to superionic phase transitions in the materials, but no phase transitions have been detected for x = 0.2 compound in the studied temperature range. Ionic conductivity and its activation energy of YSZ thick films prepared by magnetron sputtering depend on their preparation’s technological... [to full text]

The influence of the structure and elemental composition of lithium ions’ and oxygen vacancies’ (Vo) solid electrolytes (SE) on their electrical properties are investigated in the dissertation. The technological conditions of SE ceramics’ and films’ fabrication, which influence their microstructure, are described. The results of the investigation of the surfaces, temperature stability, and electrical properties are presented. Li+ SE belong to monoclinic, orthorhombic, or rhombohedral symmetries. The microstructure of the ceramics is mainly influenced by the temperature of their sintering. It has been shown by XPS that LiCe2/3PO4 ceramic is Li+-ion conductor. Complex impedance spectroscopy investigation showed that the increase of x in the systems Li1+xScxZr2-x(PO4)3, Li1+xZr2-2xAlxTix(PO4)3, and Li1+xGe2-2xAlxTix(PO4)3 (where x = 0.1, 0.2, 0.3) leads to the increase of bulk ionic conductivity of the ceramics and to the decrease of its activation energy. Phase transition temperature in Li3Sc2–xBx(PO4)3 compounds depends on x. The anomalies of temperature dependencies of bulk conductivity of Li3-xSc2-x-yYyZrx(PO4)3 system were observed when x = 0.1, y = 0, 0.1. The anomalies are related to superionic phase transitions in the materials, but no phase transitions have been detected for x = 0.2 compound in the studied temperature range. Ionic conductivity and its activation energy of YSZ thick films prepared by magnetron sputtering depend on their preparation’s technological... [to full text] / Disertacijoje yra nagrinėjama, kokią įtaką ličio katijonų ir deguonies vakansijų (Vo) kietųjų elektrolitų elektrinėms savybėms daro jų struktūra ir elementinė sudėtis. Darbe yra aprašomos technologinės superjoninių junginių (SJ) keramikų ir sluoksnių gamybos sąlygos, lemiančios jų mikrostruktūrą, bei pateikiami SJ paviršių, temperatūrinio stabilumo ir elektrinių savybių tyrimo rezultatai. Li+ SJ priklauso monoklininei, ortorombinei arba romboedrinei singonijoms. Keramikų mikrostruktūra labiausiai priklauso nuo jų kepinimo temperatūros. LiCe2/3PO4 keramiką paveikus elektriniu lauku, XPS buvo parodyta, kad šioje medžiagoje vyksta Li+ jonų pernaša. Kompleksinės varžos spektroskopijos tyrimai parodė, kad sistemose Li1+xScxZr2-x(PO4)3, Li1+xZr2-2xAlxTix(PO4)3 ir Li1+xGe2-2xAlxTix(PO4)3 (čia x = 0,1, 0,2, 0,3), didinant x, didėja kristalitiniai keramikų laidžiai, o jų aktyvacijos energijos mažėja. Li3Sc2–xBx(PO4)3 junginiuose vykstančio superjoninio fazinio virsmo temperatūra priklauso nuo x. Li3-xSc2-x-yYyZrx(PO4)3 sistemoje kai x = 0,1, y = 0, 0,1 temperatūrinėse kristalitinio laidžio prieklausose yra stebimos anomalijos, susijusios su superjoniniais faziniais virsmais šiose medžiagose, o kai x = 0,2 tirtame temperatūrų intervale faziniai virsmai nevyksta. Magnetroninio dulkinimo metodu suformuotų YSZ storųjų sluoksnių joninis laidis ir šio laidžio aktyvacijos energija priklauso nuo jų paruošimo technologinių sąlygų. Didinant NiO-CGO sluoksnių, suformuotų purškimo pirolizės... [toliau žr. visą tekstą]

The elemental composition of the samples of modern and archaeological ceramics was determined using the energy dispersive X-ray analysis, flame atomic absorption spectrometry, titrimetric and spectrophotometric analysis methods. It has been shown that the qualitative and quantitative composition of all the samples is different. It has been established that silicon and aluminium are the main elements in all the samples. SiO2 accounts for 46–60 % of the composition of the ceramics, Al2O3 – for some 17–33%. The amounts of Fe, Na, Mg, K, Ca and Ti discovered in the samples are several times lesser. EDX analysis can successfully be used in determining the main elements whose amounts exceed 0.5% of the overall elemental composition. In order to determine the exact composition of ceramics one has to employ the FAAS analysis method. To determine in a credible manner the amount of aluminium in ceramics, one can use the titrimetric method, and the amount of silicon and titanium – spectrophotometric methods. Upon examination of the modern and archaeological ceramics by diffraction analysis it has been established that the main phase of all the samples is the same – quartz SiO2, however their phase composition varies. In different samples the following phases have been discovered: calcite, dolomite, kaolinite, albite, microcline, muscovite, mullite, hematite, rutile, diopside, corundum, titanite, and sodium anorthite. Being aware of the phase composition, it has been established that the... [to full text] / Šioje daktaro disertacijoje pirmoje dalyje nustatyta šiuolaikinės, o antroje dalyje – archeologinės keramikos gaminių elementinė ir fazinė sudėtis, bei ištirta morfologija. Šiuolaikinės ir archeologinės keramikos pavyzdžių elementinė sudėtis nustatyta Rentgeno spindulių dispersinės analizės (EDX), liepsnos atominės absorbcinės spektrometrijos (LAAS), titrimetrinės ir spektrofotometrinės analizės metodais. Parodyta, kad visų keraminių pavyzdžių kokybinė bei kiekybinė sudėtis yra skirtinga Nustatyta, kad visuose keramikos mėginiuose pagrindiniai elementai yra silicis ir aliuminis. SiO2 sudaro 46 – 60% keramikos sudėties, Al2O3 – apie 17 – 33%. Fe, Na, Mg, K, Ca ir Ti mėginiuose rasta kelis kartus mažiau. EDX analizė gali būti sėkmingai naudojama nustatant pagrindinius elementus, kurių kiekiai viršija 0,5 % bendros elementinės sudėties. Norint nustatyti tikslią keramikos sudėtį ir pėdsakinius elementus reikia naudoti LAAS analizės metodą. Aliuminio kiekį keramikoje patikimai galima nustatyti titrimetriniu, o silicio ir titano kiekį – spektrofotometriniais metodais. Ištyrus šiuolaikę ir archeologinę keramiką Rentgeno spindulių difrakcine analize (XRD), nustatyta, kad visų keramikų pagrindinė fazė yra vienoda – silicio dioksidas SiO2, tačiau jų bendra fazinė sudėtis skiriasi. Skirtinguose kermikos pavyzdžiuose buvo aptikos šios fazės: kvarcas, dolomitas, kaolinas, albitas, mikroklinas, muskovitas, mulitas, hematitas, rutilas, diopsidas, korundas, titanitas, natrio anortitas... [toliau žr. visą tekstą]

The A2Mo3O12 family, where A3+ is a large trivalent cation, can show interesting thermal properties such as negative thermal expansion, also known as thermomiotic behavior, where the overall volume of the material contracts with increasing temperature. A selection of compounds in this family, namely HfMgMo3O12, In2Mo3O12, Y2Mo3O12, Al2Mo3O12, In(HfMg)0.5Mo3O12, and In1.5(HfMg)0.25Mo3O12, have been synthesized using solid-state and mechanical activation techniques as well as a simplified sol-gel approach (Al2Mo3O12). Coefficients of thermal expansion were found to range from large-negative to low-positive in the orthorhombic phase, including near-zero in In(HfMg)0.5Mo3O12 and In1.5(HfMg)0.25Mo3O12. This set of materials provided insight into the role of low-frequency phonon modes in open-framework materials. Low-temperature heat capacity and thermal conductivity measurements confirmed that low-frequency modes were active in thermomiotic materials, and also present to some extent in all members of the open-framework A2Mo3O12 family examined. A clear correlation exists between the magnitude and sign of the coefficient of thermal expansion in the orthorhombic phase and the contribution of low-energy modes to the low-temperature heat capacity, with negative thermal expansion materials having a larger contribution. The low-frequency phonon modes result in low thermal conductivity and reduced phonon mean free paths when compared to conventional ceramics and indicate that these low values are characteristic of open-framework materials in NTE families even if the materials in the families are not thermomiotic themselves.

This research strived to examine the potential for carbon fibre to improve the strength characteristics of ceramic water filters (CWFs) to improve their length of use in the field while maintaining, or improving, existing flow and bacteria attenuation capabilities. Model-scale CWF discs were made exploring several configurations of carbon fibre reinforcement and were tested for flow through rates, E coli attenuation, and equi-biaxial flexural strength. It was determined that, while the particular carbon fibre configurations explored in this study did not increase the strength of the CWF discs, they did provide some benefit such as improving flow-through rates while minimally detracting from bacteria removal. This indicates that the reinforcement of CWFs has potential and further research should be conducted to determine an appropriate reinforcement configuration to improve both their strength characteristics. Given that CWFs are gaining more widespread use in many countries worldwide, extending their lifespan of use would have significant value.

Materials are a significant aspect of architectural design, the construction components are selected for their availability, location, cultural meaning, physical characteristics and properties. The construction components are defined by their processes of fabrication and making. This thesis investigates processes of making utilizing local materials. It focuses on the relationship between raw material, fabrication, building application and spatial experiences. The proposed site is the former brickyard located outside Bridgetown, Nova Scotia, Canada. Material excavation, fabrication, and construction will all take place on-site. Through material studies, site strategies, and phased program development, it is hoped that an architectural language has been generated that successfully represents the potentials of developing underutilized locally sources material.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

This dissertation will contextualize and analyse selected works of the South African ceramist Marietjie van der Merwe (bl935 dl992; known professionally as Marietjie, aka Mariki, Marikie) between 1960-1988. The text consists of three chapters. The first chapter will outline the life of Marietjie van der Merwe, discuss her political and religious affiliations and ends with a chronological outline of her ceramics. This introductory chapter will help the reader to gain an insight into her character and personality which influenced the work she produced. The second chapter comprises two main sections. The first deals with the ceramists who influenced Marietjie's work. In her early art training years Laura Andreson, her teacher, played a key role in inspiring and influencing Marietjie's work. The Natzlers influenced Marietjie indirectly through Laura Andreson who in turn had been taught by them. Rudolf Staffel manipulated aspects in porcelain inspired Marietjie's later works of the 1980s. The second half of this chapter deals with the influence that Marietjie had on institutions and her students. The works of Katherine Glenday, a student and later colleague, are discussed and comparisons made. Marietjie van der Merwe's contributed significantly to the modernist foundations of South African studio ceramics, was mentor and studio advisor to the ceramists of Rorke's Drift Art and Craft Centre and was a lecturer at the former Department of Fine Art and History of Art, University of Natal. Links with Nordic countries and Malin Lundbohm (now Sellmann) are drawn. Throughout this chapter the artist's work is compared and discussed with that of Marietjie's. This dissertation concludes with a documentary study of six selected pieces. Original photographs facilitate visually what is been discussed in the text. These samples are found in Iziko South African National Gallery, Tatham Art Gallery and from the private collection of Lara Du Plessis. / Thesis (M.A.)-University of KwaZulu-Natal, Pietermaritzburg, 2007.

This dissertation comprises the documentation and theoretical component of a practice-led Master of Arts in Fine Art. The illustrated text focuses in four chapters on a critical explication of contemporary South African ceramists namely, Juliet Armstrong, Betsy Nield, Liza Firer and Leanne Frisinger. The dissertation includes significant discoveries about the creative use of paperclay in contemporary South African ceramics and provides documentary record of the candidate’s materials and processes. A conclusion briefly compares productions referred to in the text. / Thesis (M.A.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.