Plastic waste is a severe environmental problem in today's society which has been noticed and discussed during the last couple of years. A constant increase of production over the last decades hasled to a large amount of plastic waste ending up in oceans as microplastics. With harder restrictions of plastic use from the European Parliament, alternative plastics that are bio-based and therefore degradable have increased in demand. The aim of this project was therefore to synthesize alignocellulose-based material which contains the minimum amount of latex, the plastic component, while still satisfying the same requirements as a thermoplastic. The original idea was to create the latex with PISA-RAFT technique however, this was not possible since the needed materials could not be delivered due to COVID-19, therefore radical emulsion polymerization was carried out. Two latexes were synthesized to create composites with wheat-straw, latex A and latex B. Both latexes consisted of 75% of monomer vinyl acetate (VAc) which was the main component but with different weight percentages of monomers methacrylic acid (MAA) and methyl methacrylate (MMA). Latex A consisted of 20 % MAA and 5% MMA and latex B consisted of 20% MMA and 5% MAA. Latex A and latex B were then mixed with wheat straw to create composites. Due to problems withthe wheat-straw composites one additional composite was created to be able to do all of the analyses. This composite was created by using filter paper as biofiber to mix with the two different latexes. Various characterization analyses including FE-SEM, DLS, DSC, FTIR, NMR, TGA and tensile tests were performed on the composites. The NMR and DSC analyses indicated that the actual composition of monomers differs from the theoretical composition and demonstrates that the presence of MAA is hard to detect. This is due to the DSC value for latex A experimental Tg being lower than latex B experimental Tg when latex A consists of more MAA which has a higher detected Tg. During the NMR analysis MAA was also not detected in either latex A nor latex B. The analyses of FTIR contradicts the NMR and DSC analyses hence peaks believed to be from MAA are detected. When comparing the analysis for latex A and B, DLS analysis resulted in latex A having a low PDI and a bigger emulsion sphere size which is preferred when producing composites. The tensile test resulted in latex B achieving the higher values for Young’s modulus and max stress while latex A had a higher value for strain at break. The TGA and DSC analysis however resulted in latex B having a higher Tg and higher thermal stability. The overall analyses indicated that latex B was the most optimal choice for composite production with aslight difference. The analysis of the composites indicated by FE-SEM that the interaction between latex and filter paper were higher than for latex and wheat straw. A total of four wheat-straw composites were created with the weight-ratio of wheat-straw:latex, 50:50 and 75:50 for both latex A and B. Due to not being able to grind the wheat straw to the minimum size needed to create composites only FE-SEM and FTIR analyses of the wheat-straw composites could be made. Because of this no conclusion could be made whether the 75:50 or 50:50 weight ratio was the most optimal. / Plastavfall är ett allvarligt miljöproblem i dagens samhälle som uppmärksammats mycket under de senaste åren. En ständig ökning i produktionen under de senaste decennier har lett till att stora mängder plast hamnat i haven där de sönderdelas till mikroplaster. Med strängare krav av plastanvändning från Europaparlamentet har nya alternativa plaster som är biobaserade och därmed nedbrytbara ökat i efterfråga. Målet med detta projekt var därför att syntetisera ett lignocellulosabaserat material som innehåller så lite icke-nedbrytbar latex, plastkomponenten, som möjligt utan att behöva mista de egenskaper som efterfrågas av termoplaster idag. Den ursprungliga idén var att syntetisera latexen genom PISA-RAFT tekniken, dessvärre pga rådande omständigheter gällande COVID-19 var detta inte möjligt då materialen som behövdes inte kunde levereras. Därför syntetiserades latexen genom emulsionspolymerisation istället. På grund av problem med halmen skapades två olika typer av kompositer, halm kompositer och filterpapper kompositer. De två kompositerna gjordes i två varianter, en innehållande latex A och en med latex B. Latex A och B syntetiserades av olika mängd monomerer vilka var metakrylsyra (MAA) och metylmetakrylat (MMA). Både latex A och B innehöll 75 % av monomeren vinylacetat (VAc). Olika karakteriseringsmetoder, FE-SEM, DLS, DSC, FTIR, NMR, TGA och tensile test utfördes på kompositerna. NMR och DSC analyserna indikerade att den analyserade kompositionen av monomererna skiljer sig åt från den teoretiska kompositionen då närvaron av MAA var svår att detektera. FTIR analysen motsäger dock de analyserade värdena av NMR och DSC då MAA tros ha detekteras då. För jämförelsen av latex A och B resulterade DLS i lägre PDI och större emulsions sfärer för latex A vilket föredras vid produktion av kompositer. Genom analys av tensile test uppnådde latex B högre värden för Young`s modul och max stress medans latex A uppnådde högre värden för belastning vid brottet. TGA och DSC analysen resulterade dock i högre Tg och högre termisk stabilitet för latex B. Den övergripande analysen indikerade att latex B var det mer optimala valet för kompositproduktion meden liten skillnad i jämförelse. Analysen av kompositerna genom FE-SEM indikerade att interaktionen mellan latex och filterpapper var högre än latex och halmen. Total skapades fyra halm kompositer med halm:latex viktförhållandet 50:50 och 75:50 för både latex A och B. Till följd av att halmen inte kunde malas ned till den minimala storleken som behövdes för att bilda kompositer, kunde endast FE-SEM och FTIR analyser utföras. På grund av detta kunde ingen slutsats dras om vilket viktförhållande, 50:50 eller 75:50, som bildade den mest optimala kompositen.

Cubes of coal have been tested in compression in the past, and it has been found. that the following formula, relating the compressive strength to the size of the cube can be applied: P = k .a- n Where P is the compressive strength in pounds per square inch. a is the edge dimension os specimens tested. n is a constant. k is a constant. The value of n has been found by a majority of people working on coal to be 0.5, however, lower values have also been found. In this study limestone shale and Plaster of Paris cubes, varying in size between one and three inches, and one and five inches in the case of shale, were tested in compression. The results were converted to logarithmic form, and the value of n determined for each material. It was found for the limestone and the Plaster of Paris that the value of n was close to zero over the range of sizes tested, indicating that the strength is independent of the size of the spec1men over the range one inch to three inch cubes. A value of 0.20 was found for the shale over the range one inch to five inches. The Griffith crack theory of failure gives the following result: P = k.c -0.5 Where P is the compressive strength in pounds per square inch. 2c is the length of cracks in the material. k is a constant. Thus, depending upon the relationship between c and a, the Griffith theory predicts that the value of n should be 0.5 for cracked materials where the length of crack is directly proportional to the edge dimension of the specimen, and zero where the length of crack is independent of the edge dimension of the specimen, in relatively uncracked materials. The Griffith theory is supported both by the results of compression tests, and by the results of the tests in this study and those previously conducted on coal. / Master of Science

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

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

Orientador: Prof. Dr. Fabio Furlan Ferreira / Tese (doutorado) - Universidade Federal do ABC, Programa de Pós-Graduação em Nanociências e Materiais Avançados, 2017. / A utilização do gesso na construção civil vem crescendo por diversos fatores: baixo custo do material, disponibilidade e soluções construtivas mais rápidas. Por apresentar rápido endurecimento, o desperdício de gesso é um problema sério, uma vez que resíduos de construção e demolição com altos teores de gesso não podem ser aproveitados como agregados reciclados para concretos e sua disposição em aterros pode gerar contaminação do solo e da água, além da formação de gases tóxicos e inflamáveis. Por outro lado, a reciclagem do gesso mostra-se bastante atraente, uma vez que basta calcinar o material em temperaturas amenas (140 °C a 160 °C) para que ele volte à sua composição inicial e possa ser reutilizado. Entretanto, as características do material resultante deste tipo de reciclagem devem ser muito bem avaliadas para que este processo se torne corriqueiro. Dessa forma, este trabalho tem como objetivo avaliar o impacto da reciclagem na microestrutura e nas propriedades físicas do gesso, comparando com o material comercial. Para tanto, a principal técnica de avaliação da microestrutura utilizada neste trabalho é a difração de raios X por policristais, que, aliada ao método de refinamento de Rietveld, permite quantificar as fases presentes no material, avaliando possíveis alterações causadas pela reciclagem. Ensaios de análise termogravimétrica, microscopia eletrônica de varredura, distribuição granulométrica a laser, área superficial específica por BET, densidade de massa aparente e massa específica também foram aplicados às amostras de gessos comerciais do setor da construção de São Paulo, que passaram por um processo de reciclagem composto pelas etapas de hidratação, moagem e calcinação em laboratório, bem como para a amostra de resíduo de gesso coletado em obra, também moído e calcinado em laboratório. Medidas de DRXP in-situ, para monitoramento da hidratação do gesso, serviram de base para o refinamento paramétrico em função do tempo, que permitiu avaliar a reatividade dos gessos reciclados em comparação com as amostras comerciais. Os ensaios mostraram que o teor de água utilizado na produção do resíduo não tem impacto significativo sobre a reciclagem e que algumas marcas de gesso disponíveis no mercado da construção apresentam altos teores de impurezas. O processo de reciclagem adotado não causou alterações na composição química, mas produziu um material com maior área superficial específica e menor compacidade que o material comercial de origem, o que o tornou mais reativo, comprometendo sua aplicação por alterar a consistência e reduzir o tempo útil para utilização. Sendo assim, o sucesso da reciclagem está diretamente associado ao controle da moagem, que deve ser monitorado de maneira a garantir que o material reciclado apresente área superficial específica semelhante à do material comercial. / The use of gypsum in civil construction has been increasing due to several factors: low material cost, availability and quicker constructive solutions. Because plaster wasting rapidly, plaster waste is a serious problem, since construction and demolition wastes with high gypsum contents cannot be used as recycled aggregates for concrete and their disposal in landfills can lead to soil and water contamination, besides the formation of toxic and flammable gases. On the other hand, plaster recycling proves to be quite attractive, since it is enough to calcine the material in mild temperatures (140 °C to 160 °C) so that it returns to its initial composition and thus can be reused. However, the characteristics of the material resulting from this type of recycling should be very well evaluated for this process to become commonplace. Therefore, this work aims to evaluate the impact of recycling on the microstructure and physical properties of the gypsum, comparing to the commercial material. The main technique of evaluation of the microstructure used in this work is the X-ray powder diffraction, which, together with the Rietveld refinement method, allows quantifying the phases present in the material, evaluating possible changes caused by recycling. Thermogravimetric analysis, scanning electron microscopy, laser particle size distribution, specific surface area by BET, apparent mass density and specific mass were also applied to samples of commercial plasters obtained from São Paulo construction sector. The recycling process encompasses the steps of hydration, grinding and calcination in laboratory, as well as for the sample of gypsum residue collected on site, which was also grinded and calcined in laboratory. In-situ XRD measurements for the plaster hydration monitoring contributed for the time-based parametric refinements, which allowed the evaluation of recycled plasters reactivity compared to commercial samples. The tests showed that the water content used in the waste production does not have a significant impact on the recycling and that some brands of gypsum available in the construction market have high levels of impurities. The recycling process adopted did not cause changes in the chemical composition, but produced a material with a greater specific surface area and less compactness than the original commercial material, which made it more reactive, compromising its application by altering its consistency and reducing the useful time. Therefore, the success of the recycling is directly associated to the grinding control, which must be monitored in order to ensure that the recycled material presents a specific surface area similar to that of the commercial material.

The diploma thesis deals with the use of waste glass powder as an aggregate in thermal insulation plasters for AAC. In the theoretical part, the problem of thermal protection of buildings is discussed first. The production and properties of foamed glass are described. Then the research of plasters, their composition and properties was made. Thermal-insulating plasters are specified and their use has been proposed for thermal insulation of building structures. In the practical part, suitable formulations have been proposed in the form of dry plaster and mortar mixtures (SOMS). Test samples were prepared from them. The physical and mechanical properties were measured. These were compared with the requirements set by standards and technical regulations. To get closer to the behavior of plasters on real buildings an AAC wall was built. The individual recipes were applied on it. It was monitored working with plaster and how it held on the masonry. During ripening crack development was observed. Optimization calculation inculded these aspects and it determined the optimal recipe. All designed recipes can be used as a thermal-insulating plasters.

Globally, there is a need for alternative building materials that require less energy to produce than conventional materials. These alternative materials have gained popularity in recent years, however there is a need to better understand their physical properties in order to increase confidence in their use. As such, a testing program was undertaken to investigate the structural properties of some of these materials. A series of compressed earth blocks made from a mixture of earth and cement compressed to 8 - 12 MPa were tested for their compressive capacity in masonry prisms. The blocks had been weathered for one to two years. The blocks with no cement had a capacity of 2.22 MPa, while cement stabilized blocks had a capacity of 8.11 MPa. Weathering did not result in any significant reduction in the strength of the blocks. Bales of high density straw were tested both with and without cement plaster skins. Unplastered bales exhibited a stiffness between 0.3 - 0.7 MPa when oriented Flat, and 1.2 MPa on edge. The bales had a dilation ratio between 0.1 - 0.3 in the Flat orientation and averaging 3.5 in the Edge orientation. The high density bales plastered with cement plaster exhibited ultimate strengths averaging 171.2 kN/m. Capacity was heavily dependent on plaster strengths, and when normalized for plaster strengths, high density bales had capacities lower than those of regular density bales tested previously (34.1 kN/m/MPa compared to 44.3 kN/m/MPa). Three walls made of straw with cement plaster were constructed with pin-ended conditions to study the effects of buckling in straw bale walls. The average capacity was 12.8 kN/m/MPa when normalized for plaster strength. Pin ends resulted in plastic hinges forming more easily in the walls, and pin ended specimens had a 75% reduction in strength compared to previous tests of "standard" end conditions. Taller walls also resulted in reduced strengths. / Thesis (Master, Civil Engineering) -- Queen's University, 2013-10-30 09:26:46.491

Orientador: Silvio José Bicudo / Banca: José Roberto Santos / Banca: Abel Washington de Albuquerque / Resumo: A hipótese desse trabalho é de que o gesso de minério, associado a fonte solúvel adequada de fósforo, aplicado superficialmente em sistema plantio direto, funciona como indutor de crescimento radicular em profundidade e influencia na produtividade do milho. O objetivo desse trabalho foi avaliar a influência do gesso de minério, associado a diferentes fontes de fósforo, sobre os atributos químicos do solo, desenvolvimento do sistema radicular e produtividade da cultura do milho sob sistema de plantio direto. O estudo foi desenvolvido na Área Experimental do Centro de Ciências Agrárias, pertencente à Universidade Federal de Alagoas. O solo onde as parcelas experimentais foram instaladas é classificado como Latossolo Amarelo Coeso distrófico. O clima, de acordo com a classificação de Koeppen do tipo As, Tropical chuvoso, com verões secos. Foi utilizado o híbrido de milho BRS 3150, cultivado em sistema de plantio direto. O delineamento estatístico foi o de blocos casualisados, com parcelas subdivididas e quatro repetições. As parcelas foram constituídas pelas fontes de fósforo (superfosfato triplo - ST, superfosfato simples - SS e sem fósforo S/P). As subparcelas foram constituídas pela presença (C/G) ou ausência (S/G) de aplicação de gesso de minério. O gesso foi aplicado em superfície 30 dias antes da semeadura do milho, que foi realizada utilizando-se semeadora pneumática de tração tratorizada, com quatro linhas individuais, espaçadas de 0,80 m, colocando-se 5 sementes por metro. Na adubação, por ocasião da semeadura, toda área experimental recebeu 30 e 120 kg ha-1 de N e K2O, na forma de uréia e cloreto de potássio, respectivamente. Nos tratamentos que receberam fósforo, foram aplicados 50 kg ha-1 de P2O5 na forma de superfosfato triplo ou superfosfato simples, dependendo do tratamento. Na adubação de cobertura foram aplicados 120 kg ha-1 de N.... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The hypothesis of this work is of that the ore gypsum, applied superficially in no-tillage system, functions as inductive of root growth in depth, thus reducing the effects of short period without rain, usual in the State of Alagoas. The objective of this work was to evaluate the influence of the ore gypsum, associate with different phosphorus sources, on the soil chemical attributes, root development and maize crop yield in no-tillage system. The study was developed in the experimental area of Centro de Ciências Agrárias, belonging to the Universidade Federal de Alagoas. The soil where the experimental plots were installed is classified as Distrofic Yellow Latossol Amarelo Coeso distrófico. The climate, in accordance with the classification of Koeppen is of the type rainy tropical, with dry summers. Was used the BRS 3150 hybrid of maize, cultivated under no-tillage system. The statistical design was of randomized blocks, in split-splot scheme, and four replications. The plots were composed by phosphorus sources (triple superphosphate - ST, simple superphosphate - SS and without phosphorus S/P). The subplots was composed by with (C/G) and without (S/G) application ore gypsum. The native vegetation was desiccated, before maize sowing, with herbicide Glyfosate using 3 L ha-1. The maize was sowed 30 days after application in surface gypsum, using seeder pneumatic of mechanics traction, with four individual lines, spaced of 0.80 m, putting 5 seeds for meter. During the sowing, all experimental area received 120 and 30 kg ha-1 of N and K2O, in form of urea and potassium chloride, respectively. In the treatments that received phosphorus, 50 kg ha-1 were applied of P2O5 in form of triple superphosphate or simple superphosphate, depending of the treatment. In covering fertilization 120 kg ha-1 of N were applied. Were evaluated on the soil the chemical attributes and on... (Complete abstract click electronic access below) / Mestre

This thesis deals with an investigation of the feasibility of using the multiple-piece plaster mold as a vehicle for teaching the indirect method of sculpture to the adolescent student. It is based upon the assumption that the students involved in the processes described will have had previous experience with the tools, techniques, and materials to be used. The investigation centered around the ability of the students to express themselves through the development of a sculptural form. The teacher's role was to assist the student identifying, expressing, and evaluating his individual goals against those goals established by the teacher. Instructional goals were present, but relegated to being of secondary importance to those goals possessed by the student. My research established the physical possibilities of casting both in aluminum and concrete using the multiple-piece plaster mold. Research procedures centered around the investigations of industrial methods used in forming aluminum castings in plaster molds. My investigation revealed that solid aluminum castings in plaster molds offered exciting artistic possibilities, but that rigid control of the preparation of the molds and the casting process was necessary before aluminum casting could be introduced to the students. Concrete casting was also found to be of use in the secondary class room. Prior to the introduction of casting to the students, a questionnaire was given them to determine their sculptural concepts and their past experience with materials, tools, and techniques. The information gained gave support to the exploration of the casting process. I then formulated a unit of study designed around the student's successfully completing a solid casting in either aluminum or concrete using the multiple-piece plaster mold. This unit was presented as nine separate problems to be solved in the following sequence: designing in clay, constructing an armature, modeling a temporary clay form, forming a multiple-piece plaster mold, drying the mold, casting, chasing, applying a patina, and mounting a completed casting. The project was challenging and broadening for the majority of the students involved. They were able to use past experiences with implements, materials, and processes and incorporate these into this new learning situation. Group solutions were found to be the most useful method in solving problems in each step. Evidence suggests that group learning through association and cooperative problem solving is the most valuable result of this project. Aluminum proved to be the most popular material, but from an instructional standpoint it was found to be a much more demanding and complex material. I found that it was important for the students to have had previous experience in the use of similar materials, tools, and methods to those encountered in this project. Due to the complexity of this project, prior knowledge in sculptural concepts is also clearly indicated as being necessary. I conclude with the recommendation that this unit of study be undertaken by advanced students as a summary project after several years of study.

The objective of this thesis is to investigate the photocatalytic activity in nanosized TiO2 structures. Two different structures were used for two different reaction systems. In the first part of the study, TiO2 coated on glass beads by a sol-gel procedure were used to test the photocatalytic CO2 reduction reaction with H2O and H2 in the gas phase. The results of photocatalytic CO2 reduction reaction revealed that CO2 reduction step of the overall reaction proceeds in dark / while illumination is required for water splitting reaction. In the second part of the study, Photocatalytic oxidation activity of the commercial TiO2 powders mixed with grout and plaster were studied for a potential commercial self cleaning material. A method based on gas phase benzene oxidation was developed for testing TiO2 added cement based self cleaning surfaces. This method was used to screen 15 commercial TiO2 samples with and without cement. Based on this method a commercial TiO2 sample (S9) was selected for further use. Surface of 15 commercial TiO2 samples were characterized by using NO and CO2 as probe molecules. Photocatalytic benzene oxidation experiments showed that using TiO2 on the surface lead to more effective surfaces in terms of photocatalytic activity. TiO2 was bound to surface by inorganic materials without much activity loss. This kind of amount optimization is of commercial importance.