En els darrers anys ha augmentat de manera considerable l'interès de les empreses per l'ús de materials reciclats per a la fabricació dels seus productes. Les raons principals són l'estalvi econòmic que comporta a causa del progressiu increment del preu de la matèria primera i l'aposta per una política ambiental d'empresa, com a part de la seva responsabilitat social corporativa, en sintonia amb una sensibilitat creixent en l'opinió pública.Aquesta tesi s'ha centrat en l'estudi de la viabilitat de la utilització de materials termoplàstics reciclats per a aplicacions en el sector de l'electrònica de consum. En una primera part, s'ha estudiat la viabilitat de la substitució dels materials verges poliestirè antixoc (HIPS) i la mescla de polímers poli(èter de fenilè) amb poliestirè antixoc (PPE/HIPS) pels mateixos materials d'origen reciclat, procedents de residus industrials. En una segona part, s'ha estudiat la viabilitat de substitució dels mateixos materials verges, estudiats en la primera part, per un material reciclat diferent. Aquest material reciclat ha estat el poli(tereftalat d'etilè)(PET) provinent de la recollida selectiva d'envasos de begudes postconsum. El treball de recerca ha estudiat la variació de propietats mecàniques i tèrmiques dels materials reciclats de partida i de les mescles de material verge i reciclat, els efectes de la degradació provocats pels processos successius de transformació i la influència de càrregues minerals (fibres i microesferes de vidre) i ignifugants a base de fòsfor lliures d'halògens sobre les propietats dels materials. L'estudi realitzat sobre aquests tres materials reciclats ha permès analitzar els factors que intervenen en l'estudi de materials reciclats, conèixer-ne les possibilitats d'aplicació en el cas concret de components d'electrònica de consum i crear les bases per poder establir una metodologia per realitzar futurs estudis d'introducció de materials reciclats en altres aplicacions tecnològiques. / En los últimos años ha aumentado de manera considerable el interés de las empresas por el uso de materiales reciclados para la fabricación de sus productos. Las razones principales son el ahorro económico que conlleva a causa del progresivo incremento del precio de la materia prima y la apuesta por una política medioambiental de empresa, como parte de su responsabililidad social corporativa, en sintonía con una sensibilidad creciente en la opinión pública.Esta tesis se ha centrado en el estudio de la viabilidad de la utilización de materiales termoplásticos reciclados para aplicaciones en el sector de la electrónica de consumo. En una primera parte, se ha estudiado la viabilidad de la sustitución de los materiales vírgenes poliestireno antichoque (HIPS) y la mezcla de polímeros poli(éter de fenileno) con poliestireno antichoque (PPE/HIPS) por los mismos materiales de origen reciclado, procedentes de residuos industriales. En una segunda parte, se ha estudiado la viabilidad de sustitución de los mismos materiales vírgenes, estudiados en la primera parte, por un material reciclado diferente. Este material reciclado ha sido el poli(tereftalato de etileno) (PET) procedente de la recogida selectiva de envases de bebidas postconsumo.El trabajo de investigación ha estudiado la variación de propiedades mecánicas y térmicas de los materiales reciclados de partida y de las mezclas de material virgen y reciclado, los efectos de la degradación provocados por los procesos sucesivos de transformación y la influencia de cargas minerales (fibras y microesferas de vidrio) y ignifugantes a base de fósforo libres de halógenos sobre las propiedades de los materiales.El estudio realizado sobre estos tres materiales reciclados ha permitido analizar los factores que intervienen en el estudio de materiales reciclados, conocer las posibilidades de su aplicación en el caso concreto de componentes de electrónica de consumo y crear las bases para poder establecer una metodología para realizar futuros estudios de introducción de materiales reciclados en otras aplicaciones tecnológicas. / In recent years the interest of companies in the use of recycled materials for the manufacture of their products has increased considerably. The main reasons for this are, firstly, the economic savings offered when compared to the progressive increase in the price of the raw material and secondly, the pressure for a company to implement an environmental policy, as part of its 'corporate social responsibility', in tune with a growing sensitivity of public opinion in this area. This thesis has focussed on studying the feasibility of the use of recycled thermoplastic materials for applications in the consumer electronics sector. In the first part, it centres on the feasibility of the substitution of the virgin materials High-Impact Polystyrene (HIPS) and the mix of polymers poly(ether phenylene) with High-Impact Polystyrene (PPE/HIPS), for the same materials of recycled origin, coming from industrial waste. In the second part, it studies the feasibility of substitution of the virgin materials studied in the first part, by a different recycled material. This recycled material being the pol (ethylene terephtalat) (PET) which comes from the selective collection of post consumption drink bottles. The research work has studied the variation of mechanical and thermal properties of the original recycled materials and of the mixtures of virgin and recycled material, the effects of the degradation provoked by the successive transformation processes and the influence of mineral fillers (fibres and glass beads) and halogen-free phosphor-based flame retardants, on the properties of the materials. The study, carried out on these three recycled materials, has allowed the following: analysis of the factors that intervene in the investigation of recycled materials; knowledge regarding the possibilities of application in the case of household electronics components and it has created the bases for being able to establish a methodology for carrying out future studies on the introduction of recycled materials in other technological applications.

Orientador: Marco-Aurelio De Paoli / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-04T16:27:15Z (GMT). No. of bitstreams: 1 Araujo_OlacirAlves_D.pdf: 14865661 bytes, checksum: 2d5a2ebb5b1f2a28de895859d2f3986d (MD5) Previous issue date: 2005 / Resumo: A polianilina (PAni) é um polímero intrinsecamente condutor que apresenta potencial aplicação tecnológica, mas possui baixa processabilidade. Entretanto, se misturada a termoplásticos, que possuam propriedades mecânicas adequadas, podem ser obtidas blendas com caracteristicas de dissipação de carga eletrostática. Os plásticos dissipadores convencionais apresentam resistividade superficial que varia de 10 a 10W. Neste trabalho foi realizada a otimização da síntese da PAni dopada com ácido dodecilbenzeno sulfônico, PAni(ADBS), em escala de bancada, e posterior produção em escala pré-piloto em um reator de 10 L, usando solução etanol/água (2:5 v/v) como meio reacional, em substituição ao sistema tradicional que usa água pura. As amostras foram caracterizadas por medida de condutividade elétrica, espectroscopia no infravermelho, difração de R-X, análise elementar CHN, TGA, DSC e densidade de sólidos. Com este sistema foi possível diminuir o tempo de filtração e eliminar a etapa de purificação, mantendo as principais características da PAni(ADBS). Foram obtidos três tipos de PAni(ADBS), diferenciados pelo teor de ADBS, cuja condutividade elétrica variou de 10 a 10 Scm. A PAni(ADBS) foi utilizada na obtenção de blendas com Noryl e HIPS em misturador interno acoplado a um reômetro de torque e em extrusora dupla-rosca. Estas blendas foram caracterizadas por medida de resistência elétrica superficial e volumétrica, TGA, DSC, microscopia óptica e MEV, reometria de torque e monitoramento da fotodegradação. As blendas NoryI/PAni(ADBS) contendo maior teor de ADBS foram as que apresentaram menor valor de resistividade elétrica, com diminuição de até 8 ordens de grandeza para 40% de PAni(ADBS). As blendas HIPS/PAni(ADBS) obtidas em extrusora dupla-rosca foram utilizadas na injeção de corpos de prova para ensaios mecânicos de tração e flexão. Estas apresentaram boas propriedades mecânicas e valores de resistividade superficial típicos dos dissipadores de carga estática, 10 - 10W (2 (10 - 30% de PAni(ADBS) / Abstract: Polyaniline (PAni) is an intrinsically conducting polymer with powerful technological applications, but it has poor processability. However, when blended with thermoplastics, it is possible to obtain materiais which can be used as electrostatic dissipative materials, with surface resistivity from 10 to 10W. In this work the synthesis of polyaniline doped with dodecylbenzene sulphonic acid , PAni(DBSA), was optimized in low scale for further production in pre-pilot scale using a 10 L reactor. Ethanol/water (2:5 v/v) solution was used as solvent for synthesis instead of water, which is the most common solvent used. The samples were characterized by electrical conductivity measurements, infrared spectroscopy, X-Ray diffraction, elementary analysis (CHN), TGA, DSC, and density of solids. Using ethanol/water as solvent it was possible to reduce the time of filtration and to eliminate the purification step, maintaining the main characteristics of PAni(DBSA). It was obtained three kinds of PAni(DBSA), whose difference was the DBSA concentration, with electrical conductivity in the range of 10 - 10 Scm. PAni(DBSA) was blended with Noryl and HIPS using an internal mixer coupled to a torque rheometer and a twin-screw extruder. These blends were characterized by surface and volumetric electrical resistance measurements, TGA, DSC, optical microscopy, SEM, and torque rheometry, its photodegradation as also monitored. NoryI/PAni(ADBS) blends with higher DBSA concentration showed the lower electrical resistivity, which decreased by 8 orders of magnitude for 40% of PAni(ADBS). HIPS/PAni(ADBS) blends prepared in a twin-screw extruder were injection molded for obtain specimens for tensile and flexural tests. These blends showed good mechanical properties and surface resistivity from 10 to 10W (10 - 30% of PAni(DBSA)), indicating its as electrostatic dissipative materials. / Doutorado / Quimica Inorganica / Doutor em Ciências

No description available.

This dissertation presents contact force sensors that are based on an emerging fibre-optic sensing technology, the in-fibre Bragg grating (FBG), for contact force measurements between cartilage surfaces in the human hip. There are two main motivations for force measurement in hips (and other joints). First, there is clinical evidence that suggests excessive force magnitude and duration can cause painful degeneration of joints. Second, insights from ex vivo force measurements during simulated physiologic loading are the basis of the rationale for corrective surgeries meant to halt degeneration and restore proper joint function by restoring natural joint mechanics. The current standard tools for force measurements in joints are force/stress sensitive films. There are problems associated with inserting these films into joints that affect the force/stress measurements. To insert the films, the joint must be dissected of surrounding soft tissues and, ultimately, the joint must be taken apart (disarticulated). Following disarticulation, films are fixed to cartilage surfaces, and the joint is re-assembled so that physiologic loads can be applied. The negative consequence of dissection and disarticulation is that the natural mechanics of the intact joint are permanently lost and, therefore, film measurements do not indicate the actual joint mechanics. Moreover, covering cartilage surfaces with rigid films alters the natural contact mechanics of the joint. The force sensors presented in this dissertation are designed for local force measurement over the region of the optical fibre containing the FBG and address limitations of force/stress sensitive films. The FBG force sensors are extremely small (major diameters ranging from 0.165 mm to 0.24 mm) and can be inserted into joint spaces without dissection of soft tissues and disarticulation thereby allowing the joint to remain intact. Theoretical and experimental results indicate that FBG sensor measurements are less affected by the mechanical properties of cartilage than are film sensors. The sensors presented in this dissertation also address limitations with previous FBG based force sensors and are the first application of FBGs in intact human hips. The sensors are smaller, and therefore less invasive, and insensitive to orientation, axial strain and temperature, unlike other FBG sensors presented in the literature. / Graduate

No description available.

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.

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.

Many low-income, first-generation college students have no other choice but to work to help offset the costs associated with earning a college degree (Savoca, 2016). Meanwhile, colleges and universities have the opportunity to leverage on-campus employment as a high-impact practice (McClellan, Creager, & Savoca, 2018). High-impact practices (HIPs) are known to increase retention, persistence, and completion (Kuh, 2008). If structured with intentionality and purpose, on-campus jobs can offer low-income, first-generation college students the opportunity to participate in a HIP, while simultaneously earning an income (McClellan et al., 2018). The purpose of this intrinsic case study was to explore on-campus employment as a High Impact Practice (HIP) at Intentional Validation University (IVU). IVU is four-year university that serves a disproportionate number of students who are low-income and first-generation. In addition, IVU had an explicit organizational commitment to incorporating HIPs to achieve higher levels of student performance, learning, and development. Data sources included 26 in-depth semi-structured interviews, observations, and document analysis. In addition to cultural and structural issues related to communication, the findings revealed that there were two contrasting student employment sub-cultures. There was the validating sub-culture that serves as an example from which the larger campus can learn. The opposing sub-culture was one that was invalidating to student employees. The student employee experiences with on-campus employment varied based on their working environment, which was most often influenced by their supervisor. The intentional supervisor created a validating office-environment that elevated the student employment experience to a HIP. Additional benefits of a validating subculture included further engagement with institution and access to and activation of social capital. Based on these findings, recommendations for policy, practice, and future research are advanced.

Se estudia el comportamiento a fractura de materiales, compuestos por una matriz de plástico en la que se ha dispersado una segunda fase en forma de partículas elastoméricas. Como matriz se han utilizado dos materiales diferentes: una resina de poliéster insaturada y poliestireno. Se estudia la morfología de los materiales compuestos preparados, se determinan los parámetros de fractura y otras propiedades mecánicas, se realiza el estudio fractográfico y finalmente se analizan los resultados e identifican los mecanismos de refuerzo que han actuado en cada caso.Se demuestra que la modificación con partículas elastoméricas tanto del poliéster insaturado como del poliestireno produce una mejora de la tenacidad a la fractura.El mecanismo de refuerzo de la tenacidad para el caso de matriz termoestable es el de "crack pinning-bowing" y para el caso de matriz termoplástica es el de múltiple "crazing".

Changes in sediment morphology on the West Florida Shelf is investigated over a 14-year time period using multibeam bathymetry and backscatter in water depths between 10 m and 20 m, off the coast of Indian Rocks Beach, Pinellas County, Florida. Bathymetric surveys collected in 2002 (Kongsberg EM 3000 at 300 kHz) and 2016 (Reson 7125 at 400 kHz) were processed using CARIS Hips and Sips to create bathymetric maps and backscatter images. These data were then interpreted and compared in order to test hypotheses and answer questions related to sediment migration and sediment volume change. The following questions prompted this study: A. How mobile is the sediment on the limestone? B. What sedimentary changes occurred following the 2002 and 2003 deployments of mines for an Office of Naval Research project? C. How much sediment was removed during dredging and how closely does it compare to the Army Corps of Engineers’ reported estimate during the beach renourishment of Sand Key in 2012? In order to answer these questions, hypotheses were proposed: Hypothesis A: The sediment ridges in the study site have not migrated significantly over the limestone hard bottom during the 14-year time period (Hafen, 2001; Edwards et al. 2003). Hypothesis B: There is no change in sediment volume where the mine-like object were placed and removed after the ONR mine burial experiment (Wolfson 2005 Wolfson et al. 2007). Hypothesis C: Changes in sediment volume between 2002 and 2016 will match the amount estimated by the Army Core of Engineers who dredged the area. Results show that the sediment ridges in the study area had some migration over the limestone hard bottom during the 14-year time period. The results also found that there was a sediment volume change where mine-like objects were placed and removed during the Office of Naval Research mine burial experiment because of a dredging operation in 2012 that dredged sediment from the experimental area. Specific areas investigated that surround the dredging area showed significant loss of sediment, with the change in hydrodynamics from dredging influencing this sediment loss. The volume of sediment removed from the aforementioned dredging cut was found to be within 16% of that estimated in the Army Corps of Engineers report prior to the dredging. Geologic interpretations of the backscatter images interpreted strong backscatter returns as limestone, mid strength returns as coarse shell hash and weak returns as fine to medium-grained sediments. The weak returns were found primarily on the sediment ridges. The dredging cut showed stronger returns than the surrounding ridge, indicating that underlying coarse sediments were most likely compacted and composed of shell hash. Using satellite remote sensing as a way to gather continual repeat coverage at high resolution (2 m) data to determine absolute depth in these water depths is investigated and preliminary results suggest that processed 250 m pixel MERIS data will give a similar depth range as multibeam bathymetry. The higher-resolution 0.5 m pixel raw WorldView 2 data shows NW-SE trending structure, suggesting the seafloor morphology will be more visible.