The industrial use of recycled aluminium is greatly limited by the degraded mechanical properties due to the increased impurities. Fe, one of the common impurity content in Al alloys, is difficult to eliminate once introduced into aluminium during primary production or recycling processes. Due to the low solid solubility of Fe in Al, the formation of Fe-rich intermetallic compounds (Fe-IMCs) is inevitable, which is one of the main causes for the deterioration of mechanical properties in various cast Al alloys. In order to obtain desirable mechanical properties of recycled Al alloys, modification and refinement of the Fe-IMCs are urgently required as the compact and refined morphologies of such intermetallics are generally non detrimental to Al alloy's performance. However, manipulating the solidification behaviour of the Fe-IMCs phases, including nucleation and growth, is very challenging because of the inherently more difficult heterogeneous nucleation of the Fe-IMCs compared with that of a pure metal or a solid solution; and the strong growth anisotropy. Limited understanding on mechanisms of nucleation and growth of the multicomponent Fe-IMCs is available in the literature. The aim of this study is to gain a deeper understanding on the heterogeneous nucleation and growth behaviour of Fe-IMCs in various Al alloys. The nucleation and growth of both primary and eutectic Fe-IMCs have been investigated during various solidification conditions including a number of different cooling rates and casting temperatures. Based on the experimental results of the solidification of several ternary and quaternary alloys, effect of Mg on the solidification behaviour of Fe-IMCs was investigated. Further the surface modified TiB2 particles were used to enhance the heterogeneous nucleation of Fe-IMCs in order to refine the Fe-IMCs particles. The dominant Fe-IMC in Al-5Mg-2Si-1.2Fe-0.7Mn alloy is identified, using transmission electron microscopy (TEM), as α-AlFeMnSi with a body centred cubic (BCC) lattice structure and lattice parameter of 1.256nm. In the current alloy system, the nucleation of primary α-AlFeMnSi occur at lower cooling rate (≤0.8K/s) when required nucleation undercooling is reached, as the slower cooling rate allows longer diffusion time for the solute to form a stable nucleation embryo. When casting with 20K superheat, the size of primary α-AlFeMnSi increases gradually from 24.5±3.1μm (870K/s) to 251.3±75.3μm (0.02K/s) and the size of α-AlFeMnSi eutectic increased gradually from 102.0μm (870K/s) to 623.3μm (0.02K/s). The Fe and Mn concentration in α-AlFeMnSi appears to reduce with the increased cooling rate due to the relatively insufficient solute supply when solute concentration is low (1.2wt.% Fe and 0.7wt.% Mn). Microstructure observation reveals that the {011} plane, especially on <111> orientation, is the preferred growth orientation of BCC primary α-AlFeMnSi, resulting in rhombic dodecahedral in 3D. The eutectic α-AlFeMnSi, prefers to initiate on the primary α-AlFeMnSi. In addition to the substantial nucleation undercooling, the research revealed that the nucleation of primary α-AlFeMnSi also rely on the local solute concentration and the solute diffusion. Compared with α-Al, the growth of α-AlFeMnSi is less sensitive to the cooling rate changes due to the complexities in multi-components interaction and different diffusion efficiency of different elements. The addition of Mg to Al-1.2Fe-0.7Mn and Al-2Si-1.2Fe-0.7Mn alloys was found to lead to a morphology change of Fe-IMCs. Al6(Fe,Mn), the predominant Fe-IMC in the Al-1.2Fe-0.7Mn-xMg alloy, changed from needle morphology to interconnected lamellar morphology when Mg composition increased from 0.004wt.% to 6.04wt%. A Mg-rich layer at about 5-20nm in thickness was commonly observed on the Fe-IMC/α-Al interface in the alloys with Mg content. The eutectic lamellar spacing for Al6(Fe,Mn) increases from 1.8±0.3μm to 4.5±0.8μm when Mg content increased from 0.004wt.% to 6.04wt.%. In the case of α-Al12(Fe,Mn)3Si, the predominant Fe-IMC in Al-2Si-1.2Fe-0.7Mn-yMg alloys, its lamellar spacing of the eutectic increased from 1.4±0.3μm to 3.25±0.8μm when Mg increased from 0.04wt.% to 5.41wt.%. Owing to the strong anisotropy of the Fe-IMC crystals, the segregation of solute Mg on preferred growth orientation is higher, causing greater growth restriction on this orientation. Consequently, the growth velocity on other orientations becomes relatively more significant. To optimise the morphology of Fe-IMCs in Al alloys, a novel Αl-Ti-B(Fe) grain refiner for Fe-IMCs has been developed to enhance the heterogeneous nucleation of Fe-IMCs. The addition of the novel grain refiner to an Al-5Mg-2Si-1.2Fe-0.7Mn alloy under controlled solidification condition results in a considerable refinement of the primary Fe-IMCs from 251.3±75.3μm to 110.9±45.5μm and from 127.3±36.2μm to 76.5±18.2μm at cooling rates of 0.02K/s and 0.15K/s, respectively. TEM investigations on the refiner reveal a Fe-rich adsorption monolayer in a zigzag fashion on the prismatic planes on the boride particles. This surface modification is beneficial for the heterogeneous nucleation of the Fe-IMCs. Further investigation of the Al alloy with this grain refiner addition revealed that there existed specific orientation relationships (ORs) between TiB2 and Fe-IMCs: (001)[020]Al13Fe4 // (11-20)[10-10]TiB2, and (001)[120]Al13Fe4 ∠6.05˚ (11-20)[10-11]TiB2; (0-11)[100]α-AlFeMnSi // (0001)[-2110]TiB2, and (0-11)[111]α-AlFeMnSi ∠4.5˚ (0001)[10-10]TiB2. The Fe adsorption on substrate particle, the observed ORs between TiB2 and Fe-IMCs, and the refinement of primary α-AlFeMnSi with the addition of modified TiB2 provide evidence of structure templating and composition templating required by heterogeneous nucleation of Fe-IMCs. This research has delivered contribution to the understanding and new approach for optimizing the morphology of Fe-IMCs in the Fe-containing Al alloys. Using the slow cooling rates (≤0.15K/s), the formation compact primary α-AlFeMnSi can be considerably encouraged. With a lower casting temperature, the size and volume fraction of large Chinese-script α-AlFeMnSi can be significantly reduced. With addition of reasonable Mg content the morphology of Fe-IMC can be modified. Particularly, with the addition of the Al-Ti-B(Fe) grain refiner in well-controlled condition, the primary α-AlFeMnSi can be significantly refined. Thus, by implementing these approaches, the optimized Fe-IMC morphology in the microstructure of Fe-containing Al alloy is able to offer promising mechanical performance.

O presente trabalho tem como objetivo principal a proposta de um método para gestão de resíduos nas cervejarias do Estado do Rio Grande do Sul. Para isto, o trabalho se propõe a: (i) identificar as alternativas apontadas na literatura para reciclagem de resíduos em cervejarias; (ii) identificar, através de uma pesquisa exploratória, práticas já implementadas atualmente na indústria cervejeira do estado do Rio Grande do Sul e; (iii) priorizar as alternativas de reciclagem de resíduos identificadas. A metodologia de pesquisa utilizada é o Design Science Research sendo este a base para as etapas desenvolvidas no trabalho. O método de gestão de resíduos é apresentado e descrito para que as cervejarias executem a gestão de seus resíduos, incluindo-se proporções geradas, alternativas para a reciclagem e também uma possibilidade de retorno financeiro sobre a venda dos mesmos. Uma das principais contribuições desta tese foi criar um passo a passo para que novas cervejarias e também as já existentes no mercado do Rio Grande do Sul possam gerenciar seus resíduos de forma estruturada, buscando, ao invés do descarte inconsciente dos mesmos, a agregação de valor, o retorno financeiro e a preservação do meio ambiente. / This work has as main objective to purpose a waste management method at Rio Grande do Sul's breweries. As secundary objectives, it defines: (i) to identify the alternatives showed on the literature to breweries waste recycling; (ii) to identify, through an exploratory research, the practices that has already be implemented at the beer industry in Rio Grande do Sul and; (iii) to priorize the identified recycling alternatives. The research methotology applied is the Design Science Research, being it the basis to the steps developed in this work. The waste management method is presented and described aiming that the breweries start its waste management, including quantities, recycling alternatives and also a pay-back related to the wastes selling. One of this tesis mainly contributions was to create a step by step method to new and already running breweries in Rio Grande do Sul manage its wastes as an structured way, searching, instead of an anaware disposal, add value, obtain financial returns and to safeguard the environment.

Com o avanço da tecnologia aplicada em aparelhos celulares, são lançados no mercado modelos menores, mais leves e com maior rapidez em seu sistema operacional. Tudo isso atrai muito os consumidores, que por sua vez, trocam seus antigos aparelhos celulares por novos e modernos. Essas adesões e trocas freqüentes de aparelhos celulares geram um descarte significativo de todos os seus componentes e dentre eles a bateria. Assim, pelo fato do cobalto estar presente nesse tipo bateria e ser um metal com alto valor agregado, ele faz parte do estudo do presente trabalho. Este trabalho tem por objetivos estudar as etapas de condicionamento físico e de lixiviação como fases iniciais do processo de reciclagem de baterias de íons de lítio. Para a caracterização das baterias, as mesmas foram desmanteladas manualmente para a separação dos componentes. Os eletrodos foram caracterizados por espectrofotometria de absorção atômica, difração de raios-X e microscopia eletrônica de varredura com analise de microrregiões. Os ensaios de lixiviação foram feitos usando-se os seguintes parâmetros: pH entre 3 e 5, temperaturas de 25 e 50ºC, relação sólido/líquido de 1/5, tempos de 1 a 4h. Foram utilizados como meio lixiviante soluções de acido sulfúrico, clorídrico e nítrico. Peróxido de hidrogênio foi adicionado ao acido sulfúrico como agente oxidante. Os resultados alcançados mostraram que entre os moinhos de martelos, de facas e de bolas o que apresentou o melhor desempenho para a moagem de baterias de íons de lítio foi o moinho de facas. O bombardeamento com ultra-som faz com que haja a liberação do material ativo dos eletrodos que fica aderido aos suportes de cobre e alumínio mesmo apos moagem. A diminuição do pH de 5 para 3 e o aumento da temperatura de 25 para 50ºC causam o aumento da velocidade de lixiviação em meio sulfúrico do oxido de cobalto. A presença de agente oxidante na lixiviação acida faz com que diminua o tempo de lixiviação do oxido de cobalto. A lixiviação com acido nítrico e com acido sulfúrico com adições de peróxido de hidrogênio são os melhores meios de lixiviação quando comparados ao acido clorídrico e ao acido sulfúrico sem oxidante para as mesmas condições de pH e de temperatura. Nas etapas de extração liquido-liquido e reextração foram utilizados os seguintes parâmetros: relação orgânico-aquoso de 1/1, temperatura de 50ºC, pH 4 e tempo de 5 minutos na etapa de extração e como solução aquosa na fase da reextração o acido sulfúrico 2M. Nas duas etapas foi utilizado como extratante o Cyanex 272 diluído em querosene. Os resultados alcançados mostraram que nos primeiros dois contatos das fases orgânicas e aquosas já se obtém as melhores porcentagens de extração e reextração. A eficiência global dos quatro contatos na etapa de extração foi de 94% e na etapa de reextracao foi de 98%. / The fast changes in technologies applied to mobile phones causes an incredible appearance of new and even better models each day. As a consequence, each year increase the amounts of waste of electronic and electric equipments including batteries that should be disposed of. The goal of the present work is to study methods of physical conditioning and acid leaching of Li-ion batteries. Hand disassembling Li-ion batteries was performed to identify and characterize the components of scrap Li-ion batteries. Materials extracted form the electrodes were characterized using X-ray diffraction, atomic absorption spectrophotometry and scanning electron microscopy coupled with EDS micro-probe. Leaching tests were carried out using the following parameters: pH (3 - 5), temperature (25 and 50ºC), solid/liquid ratio equal to 1/5, leaching time (1 to 4h). Sulfuric acid, chloridric acid and nitric acid were tested as leaching media. Hydrogen peroxide was tested as an oxidizing agent during leaching tests using sulfuric acid. The results obtained showed that knives mill presented better results to grind the scraps in comparison to hammer and balls mills. Ultrasonic treatment was effective to release the active cell materials from copper and aluminum. Decreasing pH from 5 to 3, and increasing the temperature from 25 to 50ºC cause the increasing of the leaching rate of cobalt oxide. Oxidizing conditions also increase the rate of cobalt oxide leaching. Nitric acid and sulfuric acid plus hydrogen peroxide leaching results in better leaching rates compared to chloridric acid and sulfuric acid.

Os resíduos eletroeletrônicos vêm aumentando no mundo e contribuem com a escassez de recursos naturais e com a ocupação de espaços em aterros que estão esgotando sua capacidade de disposição de resíduos. Uma alternativa é a reciclagem dos resíduos eletroeletrônicos e para viabilizar o processo, é importante conhecer a composição dos materiais para direcionar tecnologias e conseguir sua recuperação. Esses resíduos possuem uma diversidade de plásticos que, ao serem reciclados, garantem o seu reaproveitamento como fonte de matéria prima para a produção de materiais poliméricos. O ABS (copolímero: Acrilonitrila Butadieno Estireno) e o HIPS (Poliestireno de Alto Impacto) são dois tipos de polímeros muito utilizados nas indústrias de eletroeletrônicos. O objetivo deste trabalho é estudar a separação do ABS e do HIPS para a reciclagem, utilizando as Técnicas de Tratamento de Minérios como a separação por flotação. Para a separação dos polímeros, os resíduos eletroeletrônicos foram desmantelados manualmente e os componentes plásticos foram separados por tipo e cor. Os plásticos separados, foram cominuídos no moinho de facas e classificados por meio do ensaio granulométrico. Os ensaios de flotação foram conduzidos em uma coluna de vidro, utilizando se de soluções de álcool etílico e de ácido acético em diferentes concentrações. As soluções atuaram como agentes hidrofilizantes de superfície, permitindo a separação desses polímeros. Na flotação com o etanol, os experimentos mostraram os melhores resultados na concentração de 20% em massa, com a pureza de HIPS de 96% e do ABS de 98%. Na flotação com o ácido acético, os ensaios mostraram os melhores resultados na concentração de 40% em massa, com a pureza do ABS de 96% e de HIPS de 86%.A flotação com 20% de concentração de etanol apresentou melhor eficácia na recuperação e na pureza do HIPS e do ABS em relação à flotação com 40% de ácido acético. / The speed in which new technologies are being developed stimulates the rapid obsolescence of electronic equipment. Hence electronic waste grows at high rates all over the world and has become an environmental issue due to its accumulation in landfills. In order to reduce these environmental impacts, a feasible solution is recycling. Recycled allows its reuse as a source of raw material for the production of polymeric materials as well as for energy generation. ABS (copolymer: Acrylonitrile Butadiene Styrene) and HIPS (High Impact Polystyrene) are the most common polymers used in the electro electronic industry. The aim of this work is to study the separation of ABS and HIPS using the froth flotation technique. Froth flotation is a process of separating the solid particles through differences in their surface characteristics. The reason for using this technique is that gravimetric methods are unlikely to produce good results due to the similar specific weights of both materials. Froth flotation also is difficult as both plastics are water repellent (hydrophobic). The samples were manually dismantled, with plastic components separated by type and color. After that, comminution was performed in a knife mill and grain sizes separated in screen. The flotation tests were conducted in a glass column, using ethyl alcohol and acetic acid solutions with different concentrations. These solutions were used to increase the hydrophilic characteristics in the surface of ABS, and to make possible the separation of these polymers. When floating with ethanol, the experiments showed the best results at a concentration of 20% in weight, with purity levels of 96% of HIPS and 98% of ABS. When floating with acetic acid, the tests showed the best results at the concentration of 40% in weight, with purity levels of 96% of ABS and 86% of HIPS.The flotation with 20% in weight of ethanol concentration showed better results in recovery and purity of HIPS and ABS in comparison to the 40% acetic acid.

A produção de mantas de tecido não tecido (TNT) por processo de extrusão a partir do poli(tereftalato de etileno) (PET) reciclado é uma forma interessante de reciclagem de polímeros adotada pela indústria que consegue conciliar viabilidade econômica com benefícios ambientais. Entretanto, durante a etapa de extrusão, muito material é perdido devido a entupimentos do equipamento ou outros motivos que acarretam na geração de uma quantidade considerável de rejeitos que não podem ser reaproveitados no sistema, devido à depreciação de propriedades ocorridas no material durante o processamento, levando ao descarte deste material geralmente em aterros sanitários. Neste trabalho foi feito um estudo sobre a reciclagem de rejeitos de PET das linhas de produção de mantas de tecido não tecido (TNT), adotando aditivos do tipo extensores de cadeia, para recuperar as propriedades que haviam sofrido grande depreciação. A incorporação de extensores de cadeia do tipo anidridos, isocianatos e fosforados, por meio de extrusão reativa, proporcionou melhorias consideráveis nas propriedades químicas, mecânicas e reológicas do rejeito de PET como aumento de massa molar, aumento de iscosidade no fundido e resistência à tração, facilitando o processamento e favorecendo a utilização do rejeito em novas etapas de reciclagem mecânica. Para as indústrias, a possibilidade de converter custos relacionados às operações de descarte de rejeitos em lucros com a agregação de valor a estes rejeitos poliméricos é extremamente interessante. Da mesma forma, a diminuição do volume de materiais poliméricos depositados no meio ambiente significa menos poluição e menos contaminação a diversos ecossistemas, apoiando os esforços que estão sendo feitos para a preservação e redução de poluentes na natureza. / The production of nonwoven fabrics (NWF) by extrusion process from recycled poly(ethylene terephthalate) (PET) is an interesting way for polymer recycling used by industry which to allow conciliate economic viability with environmental benefits. However, during extrusion step, a fraction of material is lost due to equipment clogging or others factors, leading to production of considerable amount of wastes which can not reinserted in system, due to the depreciation of material properties that occurs during thermal-mechanical processing. These rejects are generally deposited in land wastes. In this work was carried out a study about recycling of PET wastes from NWF production lines, using additives of chain extender kind to recoup properties that had been highly depreciated. The incorporation of chain extenders of kind anhydride, isocyanate and phosphorous compounds by reactive extrusion improved considerably some chemical, mechanical and rheological properties of PET waste such as increase in molecular weight, melt viscosity and strain strength, easing the thermal-mechanical processing and making possible the use of PET waste in news steps of mechanical recycling. The possibility to convert expenditures with wastes discarding operations into profits due to the values aggregation on these polymeric wastes is very interesting for the industries. Then, the decrease of amount of polymeric materials deposited in natural environment signifies less contamination to several ecosystems, supporting the works that have been realized to decrease pollutants and to preserve the nature.

Com a aprovação da Política Nacional de Resíduos Sólidos, a política de sustentabilidade tende ao reaproveitamento de resíduos, em seu ciclo ou destinação final ambientalmente adequada. Neste contexto, são apresentados neste trabalho, estudos do processo de separação de materiais metálicos e não metálicos encontrados em placas de circuito impresso de microcomputadores e a caracterização dos elementos químicos presentes. Para isto efetuou-se a trituração primária (moagem) das placas de circuito impresso, classificação granulométrica, separação de elementos metálicos e não metálicos utilizando separadores, magnético e eletrostático, separação gravimétrica com o uso de clorofórmio e bromofórmio. Para caracterização dos elementos metálicos e não metálicos, foram utilizadas as técnicas de Espectrometria de fluorescência de Raios X e Espectrometria de infravermelho. Os separadores eletrostático e eletromagnético não foram efetivos na separação de placas de circuito impresso para granulometrias inferiores a 9 Mesh. A separação dos elementos metálicos e não metálicos das amostras com granulometrias inferiores a 9 Mesh, teve eficiência parcial utilizando o clorofórmio, mas mostrou-se efetiva com a utilização do bromofórmio. Embora a separação gravimétrica, não tenha sido efetiva, as amostras foram caracterizadas. Para obter uma melhor separação dos elementos presentes na amostra de não metálicos, procedeu-se a trituração secundária (moagem) desta amostra, resultando na desagregação e separação efetiva. / With the approval of the National Solid Waste Policy, the sustainability policy tends to refer to the reuse of waste materials in its cycle or final destination, environmentally right. In this context, it is introduced in this work a study of metallic and nonmetallic materials separation, found in printed circuit boards of microcomputers and present chemical elements characterization. For this purpose it was performed the primary crushing (grinding) of printed circuit boards, particle size classification, separation of metallic and non-metallic elements by using magnetic and electrostatic separators, gravimetric separation using chloroform and bromoform. For characterization of metallic and nonmetallic elements, were used Spectrometry X-ray fluorescence and infrared spectrometry techniques. The electrostatic and electromagnetic separators were not effective in the separation of printed circuit boards for grain sizes below 9 Mesh. The separation of metallic and non-metallic elements of the samples with particle sizes less than 9 Mesh, had partial efficiency using chloroform, but was effective with the use of bromoform. Although the gravimetric separation, has not been effective, the characterized samples were. In order to get better separation of the elements present in non metallic samples it was made the secondary crushing (grinding) of this sample resulting in the breakdown and effective separation.

Os resíduos eletroeletrônicos vêm aumentando no mundo e contribuem com a escassez de recursos naturais e com a ocupação de espaços em aterros que estão esgotando sua capacidade de disposição de resíduos. Uma alternativa é a reciclagem dos resíduos eletroeletrônicos e para viabilizar o processo, é importante conhecer a composição dos materiais para direcionar tecnologias e conseguir sua recuperação. Esses resíduos possuem uma diversidade de plásticos que, ao serem reciclados, garantem o seu reaproveitamento como fonte de matéria prima para a produção de materiais poliméricos. O ABS (copolímero: Acrilonitrila Butadieno Estireno) e o HIPS (Poliestireno de Alto Impacto) são dois tipos de polímeros muito utilizados nas indústrias de eletroeletrônicos. O objetivo deste trabalho é estudar a separação do ABS e do HIPS para a reciclagem, utilizando as Técnicas de Tratamento de Minérios como a separação por flotação. Para a separação dos polímeros, os resíduos eletroeletrônicos foram desmantelados manualmente e os componentes plásticos foram separados por tipo e cor. Os plásticos separados, foram cominuídos no moinho de facas e classificados por meio do ensaio granulométrico. Os ensaios de flotação foram conduzidos em uma coluna de vidro, utilizando se de soluções de álcool etílico e de ácido acético em diferentes concentrações. As soluções atuaram como agentes hidrofilizantes de superfície, permitindo a separação desses polímeros. Na flotação com o etanol, os experimentos mostraram os melhores resultados na concentração de 20% em massa, com a pureza de HIPS de 96% e do ABS de 98%. Na flotação com o ácido acético, os ensaios mostraram os melhores resultados na concentração de 40% em massa, com a pureza do ABS de 96% e de HIPS de 86%.A flotação com 20% de concentração de etanol apresentou melhor eficácia na recuperação e na pureza do HIPS e do ABS em relação à flotação com 40% de ácido acético. / The speed in which new technologies are being developed stimulates the rapid obsolescence of electronic equipment. Hence electronic waste grows at high rates all over the world and has become an environmental issue due to its accumulation in landfills. In order to reduce these environmental impacts, a feasible solution is recycling. Recycled allows its reuse as a source of raw material for the production of polymeric materials as well as for energy generation. ABS (copolymer: Acrylonitrile Butadiene Styrene) and HIPS (High Impact Polystyrene) are the most common polymers used in the electro electronic industry. The aim of this work is to study the separation of ABS and HIPS using the froth flotation technique. Froth flotation is a process of separating the solid particles through differences in their surface characteristics. The reason for using this technique is that gravimetric methods are unlikely to produce good results due to the similar specific weights of both materials. Froth flotation also is difficult as both plastics are water repellent (hydrophobic). The samples were manually dismantled, with plastic components separated by type and color. After that, comminution was performed in a knife mill and grain sizes separated in screen. The flotation tests were conducted in a glass column, using ethyl alcohol and acetic acid solutions with different concentrations. These solutions were used to increase the hydrophilic characteristics in the surface of ABS, and to make possible the separation of these polymers. When floating with ethanol, the experiments showed the best results at a concentration of 20% in weight, with purity levels of 96% of HIPS and 98% of ABS. When floating with acetic acid, the tests showed the best results at the concentration of 40% in weight, with purity levels of 96% of ABS and 86% of HIPS.The flotation with 20% in weight of ethanol concentration showed better results in recovery and purity of HIPS and ABS in comparison to the 40% acetic acid.

Doctoral Dissertation abstract: Since the term learning object was first published, there has been either an explicit or implicit expectation of reuse. There has also been a lot of speculation about why learning objects are, or are not, reused. This study quantitatively examined the actual amount and type of learning object use, to include reuse, modification, and translation, within a single open educational resource repositoryâConnexions. The results indicate that about a quarter of used objects are subsequently reused, modified, or translated. While these results are repository specific, they represent an important first step in providing an empirical evaluation of the frequency and some reasons for reuse, as well as establishing metrics and terminology for future studies.

This senior thesis in environmental analysis explores the Zero Waste ideal and its practical application to a college campus. Given the growing global trash crisis and its grave environmental, social and economic consequences, the Zero Waste movement argues for a holistic shift from ‘end of pipe’ disposal practices to those that promote the cyclical use of materials, with little-to-no matter ending up in the landfill or incinerator. Cities and colleges around the world have adopted these Zero Waste goals in an effort to function as more sustainable, efficient and moral entities. With a case study of Pomona College, I assess the current status of waste production and diversion and identify opportunities to move the College towards its 2030 Zero Waste goal and to continue its growth as a resource-wise campus. Though the College has made substantial strides towards sustainability, significant room for improvement remains, particularly in regard to waste. Various infrastructural, political, educational, data driven and cultural changes are recommended to reduce waste at Pomona College and to evolve students into conscientious resource-users on campus and beyond.

The prediction of self-reported recycling behaviors was examined using variations and expansions of Ajzen's theory of planned behavior. Three hundred and forty-eight residents from the Multnomah, Clackamas and Washington counties in Oregon completed a questionnaire that assessed attitude, subjective norms, perceived behavioral control, intentions, self-reports of recycling behavior, moral obligation and past behavior. Recycling behaviors and intentions were grouped into three categories of difficulty by a factor analysis. Structural equation analysis did not support Ajzen's model. It was found that although attitudes was correlated with the antecedent variables, it did not directly influence intentions or behaviors. Perceived behavioral control had the largest direct influence on behavior. Subjective norms had the greatest direct influence on intentions. Past behavior, as measured, was not significantly related to any variable in the model. The inclusion of moral obligation added significantly to the ability to predict recycling behavior. Moral obligation directly influenced subjective norms, attitude, perceived behavioral control and behavior. The results suggest that programs that aim to increase recycling behaviors should focus on: the community good as the motivation for recycling, the impacts of the individual's recycling behavior on community resources, the "how to's" of recycling, and supplying services and information about those services.