Una alternativa al tratamiento de aguas residuales urbanas mediante lodos activos son los sistemas de biomasa granular. Las características morfológicas de la biomasa granular le confieren, principalmente, dos ventajas sobre la biomasa floculenta: (i) la habilidad de sedimentar más rápido, y (ii) la posibilidad de realizar simultáneamente procesos aerobios, anóxicos y anaerobios dentro. Dos sistemas basados en biomasa granular han demostrado potencial en el tratamiento de aguas urbanas. En primer lugar, los reactores secuenciales granulares (GSBR), donde se llevan a cabo los mismos procesos biológicos que en los sistemas de lodos activos, pero con las ventajas de la biomasa granular. En segundo lugar, un tratamiento de aguas residuales urbanas basado en tecnología anammox, el cual permitiría una depuración de aguas sin aporte o incluso productora de energía. Esta tesis busca incrementar el conocimiento de estos sistemas de biomasa granular, con el objetivo último de confirmar si la biomasa granular puede ser una alternativa real al tratamiento de aguas residuales urbanas con lodos activos. Para el tratamiento de aguas residuales urbanas con GSBRs, se realizaron dos estudios diferentes. En primer lugar, se estudió el tratamiento un agua residual de baja carga en un GSBR a escala piloto operado durante 11 meses. Se obtuvieron y mantuvieron gránulos maduros durante 5 meses. La eliminación biológica de nitrógeno fue principalmente vía nitrito. La eficacia de nitrificación fue del 75% y se obtuvo desnitrificación simultánea a la nitrificación durante las fases aerobias del GSBR. Se observó una acumulación progresiva de sales de fósforo (probablemente apatita) entre los días 150 y 300, que pudo influir negativamente en desestabilización de los gránulos al final del periodo experimental. En segundo lugar, se llevó a cabo un estudio mediante modelización matemática para determinar estrategias de control automático que permitan mejorar la eliminación biológica de nitrógeno en un GSBR. Se diseñaron simulaciones específicas para elucidar el efecto sobre la eficacia de nitrificación-desnitrificación de la concentración de oxígeno disuelto, el tamaño de gránulo, la ratio C/N del afluente y la carga volumétrica de nitrógeno. Los resultados de las simulaciones mostraron que se pueden obtener altas eficacias de eliminación de nitrógeno simplemente fijando la consigna de oxígeno disuelto apropiada. Esa consigna apropiada se puede encontrar fácilmente en función de la concentración de amonio en el efluente. Se usaron estos resultados para proponer una estrategia de control que mejorara la eficacia de eliminación de nitrógeno. Respecto al tratamiento de aguas residuales urbanas basado en tecnología anammox en un sistema de 2 etapas, se realizaron dos estudios adicionales. En el caso de la nitritación parcial, se operó un reactor granular de 2.5L trabajando en continuo, tratando un agua residual con una concentración de nitrógeno baja y a bajas temperaturas. Se obtuvo, durante más de 450 días, un efluente adecuado para alimentar un reactor anammox posterior, incluyendo más de 365 días a temperaturas iguales o menores a 15 ºC. Se usó un modelo matemático ya existente para explorar las razones que permitieron obtener nitritación parcial a temperaturas tan bajas. Finalmente, se usó la técnica de la pirosecuenciación para explorar cambios en la estructura de la comunidad microbiana de un reactor granular anammox tras un choque térmico. Tras el choque térmico, la capacidad de eliminación de amonio se redujo un 92%. Los resultados de la pirosecuenciación indicaron que la diversidad microbiana en el reactor aumentó a medida que el reactor se recuperaba del choque térmico. En general, los resultados de la pirosecuenciación fueron acordes con los resultados de eliminación de nitrógeno y con los test de actividad anammox realizados durante el proceso de recuperación. Se usó un primer anammox específico para determinar con precisión las especies anammox en el reactor. / Granular biomass has been proposed as an alternative to activated sludge for the sewage treatment. The morphological characteristics of granular biomass, provides granules two main advantages over flocular biomass: (i) the ability of settling faster, and (ii) the possibility of performing aerobic, anoxic and anaerobic processes simultaneously. Two different granular systems have a demonstrated potential for the treatment of urban wastewater. First, aerobic granular sequencing batch reactors (GSBR), which perform the same nutrient removal process occurring in activated sludge systems, but taking advantage of the abovementioned granular sludge properties. Second, an anammox-based sewage treatment, which could allow obtaining a more sustainable (energy-neutral or even energy-positive) wastewater treatment. This thesis is focused in improving the knowledge of these granular biomass systems towards confirming granular biomass as a real alternative to urban wastewater treatment with activated sludge. For urban wastewater treatment with GSBRs, two different studies were done. First, the stability of granules and their performance at pilot scale were first studied in a 100 L GSBR treating low-strength wastewater for simultaneous carbon, nitrogen and phosphorus removal was operated for eleven months. Mature granules prevailed in the GSBR during a period of five months. The biological nitrogen removal with mature granules was mainly performed via nitrite. Nitrification efficiency was higher than 75% and occurred simultaneously with denitrification during the aerobic phase of the GSBR. A progressive accumulation of P-salts (probably apatite), was found from days 150 to 300, which could enhance the destabilization of granules at the end of the experimental period. Second, a model-based study was carried out to determine the guidelines to design an automatic control strategy with the final aim of enhancing biological N-removal in a GSBR. Specific simulations were designed to elucidate the effect of DO concentration, granule size, influent C/N ratio and NLR on the nitrification-denitrification efficiency. Simulation results showed that, in general, high N-removal efficiencies (from 70 to 85 %) could be obtained only setting the appropriate DO concentration. That appropriate DO concentration could be easily found based on effluent ammonium concentration. Those results were used to propose a control strategy to enhance N-removal efficiencies. Regarding the anammox-based sewage treatment in a two-step system, two additional studies were carried out. For the partial nitritation step, a bench-scale granular sludge bioreactor was operated in continuous mode with a low nitrogen concentration wastewater at low temperatures. An effluent suitable to feed a subsequent anammox reactor was maintained stable during more than 450 days, including more than 365 days at temperatures equal or lower than 15ºC. A previously existing mathematical model was used to determine why partial nitritation was feasible. Simulations showed that NOB was only effectively repressed when their oxygen half-saturation coefficient was higher than that of AOB. Simulations also indicated that a lower specific growth rate of NOB was maintained at any point in the biofilm due to the bulk ammonium concentration imposed through the control strategy. Finally, pyrosequencing technique was used to explore the microbial community structure changes during the recovery process of an anammox granular reactor after a temperature shock. The temperatures shock reduced the nitrogen removal rate up to 92% compared to that just before the temperature shock, and it took 70 days to recover a similar nitrogen removal rate to that before the temperature shock. Pyrosequencing results indicated that microbial diversity in the reactor decreased as the reactor progressively recovered from the temperature shock. In general, pyrosequencing results were in agreement with N-removal performance results and SAA measured in the reactor during the recovery process. An anammox specific primer was used to precisely determine the anammox species in the biomass samples.

L’Oceà Atlàntic Nord i l’Oceà Àrtic són components essencials per la regulació de la variabilitat climàtica a Europa. En aquesta regió, les reconstruccions climàtiques de temperatura superficial del mar (SST) que cobreixen els darrers 2000 anys a alta resolució són escasses. Obtenir noves reconstruccions climàtiques a l’Atlàntic Nord a alta resolució és rellevant per tal d’entendre millor com funciona el sistema climàtic. En base a aquestes reconstruccions, es pot conèixer com ha variat el clima durant els darrers mil·lenis, encabir l’actual escalfament global en un context més ampli i investigar si els modes de variabilitat climàtica natural que s’han definit a través d’observacions instrumentals recents també afectaren el clima en el passat. Aquesta Tesi Doctoral té per objectiu generar noves reconstruccions de variabilitat climàtica a escala multidecadal a la regió de l’Oceà Atlàntic Nord pels darrers 2000 – 4400 anys, analitzant proxies geoquímiques orgàniques (biomarcadors) en registres sedimentaris marins. S’ha reconstruït la variabilitat climàtica en les dues entrades principals de la corrent de l’Atlàntic Nord a l’Oceà Àrtic – l’est de l’Estret de Fram i el mar de Barents – i també en una regió especialment sensible als canvis en els modes de variabilitat climàtica natural i a la interacció entre l’Oceà Atlàntic Nord i el clima continental Europeu – el Skagerrak -. S’han utilitzat tant proxies orgàniques ben establertes (i.e. alquenones) com proxies climàtiques desenvolupades recentment (IP25 i proxies basades en GDGTs), per tal de produïr reconstruccions basades no només en SST però també en paràmetres climàtics adicionals tals com la variabilitat en la coberta de gel marí, la temperatura de l’aire i la productivitat marina exportada. A més, s’ha estudiat l’aplicabilitat de les noves proxies basades en GDGTs en el registre marí del Skagerrak i en sòls localitzats al sud de Noruega i als Pirineus. Les SST estimades amb el proxy TEX86 mostren valors similars a la temperatura mitjana anual de la zona mentre que les temperatures de l’aire reconstruïdes amb el MBT/CBT s’apropen als valors instrumentals de l’estiu per a aquesta regió. Aquest esbiaixament no és degut a canvis en la síntesi dels GDGTs en els sòls durant un cicle annual, ni a un transport preferent dels lípids amb el Riu Glomma durant aquest període. Probablement, al Skagerrak, els GDGTs són una mescla entre lípids transportats des de latituds més baixes i producció in situ en aquesta zona. Suggerim que per a obtenir reconstruccions acurades utilitzant aquestes proxies al Skagerrak, caldria primer investigar-ne el seu origen. Dels registres climàtics generats a l’est de l’Estret de Fram i al mar de Barents, interpretem que hi va haver un increment progressiu en la temperatura o en el transport de calor de la Corrent de l’Atlàntic Nord cap a l’Àrtic. Aquesta tendència va començar als anys ~1000 – 1300 AD però s’accentuà des de ~1500 - 1600 AD fins al present. Al Skagerrak, una zona influenciada per un 90% de massa d’aigua procedent de l’Atlàntic Nord, hi va haver un refredament de la SST fins a 1300 AD que es va veure revertit per un escalfament des de 1600 AD tot i que la insolació va continuar decreixent. Suggerim que les tendències d’escalfament observades en els tres registres durant els últims ~400 anys podrien estar causades per canvis en modes de variabilitat climàtica tals com un increment en la freqüència mitjana de fases positives de la Variabilitat Multidecadal de l’Àrtic, la Oscil·lació de l’Atàntic Nord o la Oscil·lació Multidecadal de l’Atlàntic. L’impacte antropogènic sobre el clima estaria sobreposat a una tendència climàtica d’escalfament que hauria afectat de forma progressiva les zones d’estudi durant els darrers ~400 anys. / The North Atlantic and Arctic Oceans play an important role in modulating European climate variability. Oceanic records of sea surface temperature (SST) variability covering the last 2000 years at high resolution in this region are scarce. Obtaining new high resolution reconstructions in this area is necessary to increase the level of understanding on how the climate system has varied during the last millennia, to put the recent warming into a wide context and to investigate if the natural modes of climate variability observed from instrumental records can be projected to the past. This PhD thesis focuses on generating new records of multidecadal climate variability in the North Atlantic Ocean, analyzing organic proxies (biomarkers) in marine sedimentary cores that cover the last 2000 – 4400 years. We generated new climate reconstructions in the two main paths where the northward flowing North Atlantic current meet the Arctic Ocean - the eastern Fram Strait and the Barents Sea - and also in a highly sensitive area to changes in the internal modes of climate variability and the interaction between the North Atlantic Ocean and European climate - the Skagerrak -. We used well established organic proxies (i.e. alkenones) but also recently developed ones (IP25, GDGT based proxies) to produce reconstructions based on SST but also on additional climate parameters such as sea ice cover variability, mean air temperature and export productivity. In addition, we tested the applicability of the relatively new proxies based on GDGTs in a marine sedimentary core from the Skagerrak and in soils from southern Norway and the Pyrenees. The TEX86 gave SST estimates that were similar to regional annual means in the Skagerrak but the MBT/CBT air temperature estimates were closer to summer temperatures. This bias towards a specific season was not due to changes in the synthesis of GDGTs in soils through an entire annual cycle or to an enhanced transport of the lipids to the Skagerrak with the Glomma River during this period. We suggest that the GDGTs in the Skagerrak might be a result of a mixture between lipids transported from southernmost locations and in situ production. The origin of these lipids in the Skagerrak should be addressed before applying these proxies in this area with reliability. From the records located in the eastern Fram Strait and the Barents Sea, positioned in the two main paths where the northward flowing North Atlantic Current meet the Arctic, we interpret there was a progressive increase in temperature probably due to a warming in or an enhancement of the North Atlantic Current. This trend started at ~1000 – 1300 AD but was accentuated from ~1500 - 1600 AD until the most recent part of the records. In the Skagerrak, an area influenced by 90% North Atlantic water, a long term cooling that lasted until AD 1300 was reversed by a progressive warming since AD 1600 until present even though insolation continued to decrease. We suggest that the warming trends observed in the three records during the last ~400 years were caused by changes in internal modes of climate variability such as more frequent predominantly positive phases of the Arctic Multidecadal Variability, the North Atlantic Oscillation or the Atlantic Multidecadal Oscillation. The impact of human activity on climate might be superimposed on a longer term warming trend caused by changes in natural modes of climate variability that progressively affected the study areas during the last ~400 years.

Es va gestionar l'operació d'un biofiltre percolador (BTF) durant un període total de 990 dies per a la dessulfuració d'un biogàs sintètic contenint 2,000 ppmv d’H2S (≈ 50 g S-H2S·m-3·h-1), utilitzant un material de rebliment aleatori (anelles Pall d'acer inoxidable). Després de l'optimització de l'operació a pH neutre, es va estudiar l'eliminació simultània de metilmercaptà (CH3SH) i H2S. A continuació es va executar la transició ininterrompuda des de 440 dies a pH neutre (6.0 – 6.5) a 550 dies a pH àcid (2.50 – 2.75). Paral·lelament es van desenvolupar eines per a la monitorització en línia d’H2S, sulfur dissolt total (TDS = H2S(aq) + HS- + S2-) i sulfat (SO42-), aplicant elèctrodes selectius d'ions (ISEs). Es va emprar un ISE de membrana cristal·lina en el sistema analític proposat, que consisteix en un analitzador per injecció de flux (FIA) per anàlisi de TDS integrat com a detector en un analitzador de flux continu amb una etapa prèvia de difusió de gas (GD-CFA) per l’anàlisi d’H2S, el qual es va mostrar idoni per a la monitorització en línia del BTF. Es va realitzar l'estudi preliminar de la determinació en línia de SO42- utilitzant un ISE de membrana líquida polimèrica, preparada amb un ionòfor comercial. No obstant això, es va obtenir baixa selectivitat per al SO42- en presència d'anions interferents, el que desaconsella l'aplicació dels elèctrodes construïts. Es van optimitzar paràmetres operacionals del BTF a pH neutre, com ara la taxa d'aeració, la velocitat de percolació (TLV) i el temps de residència hidràulica (HRT), obtenint una mínima producció de sofre elemental (S0). També es va estudiar la resposta del BTF enfront del temps de contacte del gas (EBRT) i de la càrrega aplicada (LR) d’H2S. La capacitat d'eliminació (EC) màxima va ser de 135 g S-H2S·m-3·h-1. Per a un EBRT de referència de 131 s, l'eficàcia d'eliminació (RE) va ser superior al 99%. Es va investigar l'eliminació simultània de CH3SH i H2S a pH neutre, a concentracions normalment trobades en biogàs (2,000 ppmv d’H2S i 10 – 75 ppmv de CH3SH). Les màximes EC trobades van ser de 1.8 g S-CH3SH·m-3·h-1 i 100 g S-H2S·m-3·h-1. La presència natural de CH3SH en el biogàs va ser considerada beneficiosa per l’efecte de descolmatació del llit produït pel consum de S0 per reacció química amb CH3SH. Finalment, es va caracteritzar l'operació a llarg termini del BTF sota condicions àcides de pH en funció del EBRT i la LR, obtenint una ECmax de 220 g S-H2S·m-3·h-1. Es va estudiar el perfil d'eliminació d’H2S i es va avaluar la velocitat d'oxidació del S0 acumulat dintre del llit durant episodis periòdics d'inanició. Els resultats indiquen que el primer terç del llit és responsable pel 70 – 80% del total eliminat d’H2S. L'oxidació de S0 a SO42- se suggereix com una estratègia de control contra la colmatació del llit per sofre. Tot i la important quantitat de S0 produït a pH àcid, la capacitat de dessulfuració global del BTF va ser comparable a l'obtinguda anteriorment a pH neutre. / The performance of an aerobic biotrickling filter (BTF) was assessed during a total period of 990 days on the desulfurization of a synthetic biogas containing 2,000 ppmv of H2S (≈50 g S-H2S·m-3·h-1), using a metallic random packing material (stainless steel Pall rings). After the optimization of the operation at neutral pH, the simultaneous removal of methylmercaptan (CH3SH) and H2S was studied. Afterwards, the uninterrupted transition from 440 days at neutral pH (6.0 – 6.5) to 550 days at acidic pH (2.50 – 2.75) was performed. In parallel, sensing tools for the on-line monitoring of H2S, total dissolved sulfide (TDS = H2S(aq) + HS- + S2-) and sulfate (SO42-) were developed applying ion-selective electrodes (ISEs). An ISE of crystalline membrane was used in the proposed analytical system, consisting in a flow injection analyzer (FIA) for TDS detection integrated as a detector into a continuous flow analyzer with a gas diffusion step (GD-CFA) for H2S detection, which was proven to be reliable for on-line monitoring of the BTF. The preliminary study on the on-line determination of SO42- was performed by an ISE of polymeric liquid membrane, prepared with a commercial ionophore. However, low selectivity to SO42- was found in the presence of interfering anions, discouraging the application of constructed electrodes. Operational parameters of the BTF were optimized under neutral pH, such as the aeration rate, the trickling liquid velocity (TLV) and the hydraulic residence time (HRT), achieving a minimum elemental sulfur (S0) production. Also, the behavior of the BTF was studied as a function of the empty bed residence time (EBRT) and the H2S loading rate (LR). A maximum elimination capacity (EC) of 135 g S-H2S·m-3·h-1 was found. Removal efficiency (RE) above 99% was obtained at the reference EBRT of 131 s. The simultaneous removal of CH3SH and H2S was investigated at neutral pH, for concentrations commonly found in biogas (2,000 ppmv of H2S and 10 – 75 ppmv of CH3SH). Maximum ECs were 1.8 g S-CH3SH·m-3·h-1 and 100 g S-H2S·m-3·h-1. The natural presence of CH3SH in biogas was considered beneficial because of the unclogging effect produced by the consumption of S0 by chemical reaction with CH3SH. Finally, the BTF long-term operation under acidic pH was characterized in terms of EBRT and LR, obtaining an ECmax of 220 g S-H2S·m-3·h-1. The H2S removal profile was assessed and the oxidation rate of S0 accumulated inside the filter bed was evaluated by periodical H2S starvation episodes. Results indicate that the first third of the filter bed is responsible for 70 to 80% of the total H2S removal. Oxidation of S0 to SO42- was suggested as a S-clogging control strategy under acidic conditions. Despite the important amount of S0 produced under acidic pH, overall BTF desulfurizing capacity was comparable to that obtained previously under neutral pH.

Hindcasts from the Directional Ambient Noise Estimation System (DANES) model were compared to in situ ambient noise measurements to determine the accuracy of the U.S. Navy's ambient noise model. One hundred fifty eight (158) sonobuoy ambient noise measurements were acquired at eight locations in the Northeast Pacific (NEPAC) Ocean during November and December 1980. For each sonobuoy observation a DANES hindcast was made using archived fields from Fleet Numerical Oceanography Center for the simultaneous time and location. The difference between the predictions and measurements was calculated. A maximum mean error of 4.9 dB occurred at 200 Hz which appeared to be due to errors in the DANES Historical Temporal Shipping (HITS) data base. The model was insensitive to synoptic shipping, sound speed profiles and wind field inputs when the HITS data base was utilized.

This thesis explores the trajectory that the developing technological fields of Ambient Intelligence and Persuasive Technologies introduce new intricate relationships beyond fundamental use and availability because they change our abilities to act. Since its classic articulation by Hegel (1927) philosophical explication of the relationship between people and technology states that technology is a mediating factor between people and the world. Associated with this view, which has characterized the resulting phenomenology and philosophy of technology for nearly two decades, is an understanding of technology as a form of alienation. In this dissertation the author shows how this old interpretation of the relationship between a person and their tool has emphasized how the person is active whilst the tool is passive. This traditional distinction fails to grasp the complex interaction between people and technology in the contemporary world. The nature of new technologies and novel theoretical work in this field suggests that this critical framework is now inadequate. Today, technology mediates the relationship between people and the world in increasingly complex and often collective ways. McLuhan (1967) stated: “Media evoke in us unique ratios of sense perceptions. The extension of any one of these senses alters the way we think and act”. As Greenfield (2006) and Fogg (2002) also posit, certain Ambient Intelligence and Persuasive Technologies are in-principle shaping everyday human behaviours in radically new ways. In particular, I explore how new technologies like those developed in the Artificial Companions Project can impact on our understanding of intimacy and identity. Indeed, Ambient Intelligence Technologies may play the role of reference groups (Shibutani 1987), groups who are real or imaginary and whose standpoints are being used as the frame of reference for the human actor. Given that these technologies have continuously reconfigured identification and profiling practices, this analysis rephrases insight of philosophers like Paul Ricoeur (1990), George Herbert Mead (1959) and Helmuth Plessner (1975) to trace how: The construction of our identity is mediated by how we profile others as profiling us. Thus, new technologies can become reference groups, encroaching on our everyday activities and even affecting our moral decision-making processes. As genuine upgrades of our practical space, they are destined to play a larger formative role in people’s lives in the future. Following Heidegger in Das Ding (Heidegger 1951), Latour once framed the wider social role of technologies as res publica or ‘public things’ (Latour 2005). He pointed out that the old German word ‘ding’ etymologically did not only infer ‘material object’ but also to assembly as gathering space - that thing that can bring together what it separates. Following Latour, Verbeek states that technological ‘things’ do not only mediate our existence, but are places where these mediations are made explicit – therefore, Verbeek argues, they are the places where people have to start to discuss and criticise the quality of the ways in which these ‘things’ help to shape our daily lives (Verbeek 2008). This thesis attempts to offer a new approach to this criticism through theoretical comparison and transdisciplinary analysis.

Our society is changing. The role which information and communication technologies (ICT) play in our society is growing rapidly and meanwhile the world’s population is ageing. ICT has enabled social network sites (SNS), which are often targeted towards younger people and is therefore less suitable for seniors who find themselves displaced again and again. Through a design research oriented study, we explored the theories of non-traditional computing to find alternative ways of using technology to better meet the needs of seniors. We have found bridging technologies to be a promising domain that could help address the life-changing consequences of population ageing. We have identified four design principles to support the design of bridging technologies, geared towards enabling seniors to interact with social network sites. These principles constitute our final contribution.

Los pueblos indígenas se enfrentan a un creciente número de amenazas causadas por el Cambio Ambiental Global. Dado el ritmo sin precedentes de los cambios ambientales actuales, los investigadores debaten si dichas amenazas podrían perjudicar también la capacidad de adaptación que confiere el conocimiento indígena. Al hallarse a caballo entre las ciencias naturales y sociales, la etnoecología cuenta con una posición estratégica para examinar hasta qué punto el conocimiento indígena puede ayudar a la adaptación ante cambios ambientales rápidos. Esta tesis doctoral es el resultado de un estudio interdisciplinar de tres años que aborda las relaciones entre el Cambio Ambiental Global y el Conocimiento Ambiental Local de una sociedad nativa de la Amazonia boliviana: los cazadores-recolectores tsimane’. Al enfrentarse a condiciones socio-ecológicas cambiantes y estando aún muy alejados del discurso científico sobre el cambio global antropogénico, los Tsimane’ constituyen un caso de estudio adecuado para entender cómo las percepciones locales del Cambio Ambiental Global son captadas en la memoria social de los pueblos indígenas. La principal línea argumental del presente trabajo es que el Cambio Ambiental Global cuenta con manifestaciones directas a escala local, incluyendo cambios en el clima, el ecosistema y la disponibilidad de recursos naturales. En sus cuatro capítulos centrales, esta disertación investiga de forma empírica: (a) el uso potencial del conocimiento indígena para complementar los modelos científicos que evalúan el cambio climático; (b) la relación entre las observaciones locales de cambio climático y la asimilación de información científica; (c) los límites de la capacidad adaptativa del Conocimiento Ambiental Local en un contexto de cambio rápido; y (d) el papel de las percepciones locales de cambio como estímulo de adaptación a los impactos ecológicos. Esta investigación incluyó la recolección de datos cualitativos y cuantitativos durante 15 meses de trabajo de campo en 23 comunidades del Territorio Tsimane’. Utilicé métodos comunes en investigación etnoecológica tales como la observación participativa, los grupos focales, y la recogida sistemática de datos. Realicé específicamente entrevistas semi-estructuradas sobre la percepción de cambio ambiental (n = 300 adultos), pruebas de conocimiento para evaluar los niveles individuales de Conocimiento Ambiental Local (n = 99) y una prueba controlada aleatorizada (n = 442). Adicionalmente, se recogieron datos climáticos y ecológicos para obtener estimaciones científicas de los cambios ambientales en el área de estudio. Los resultados de esta disertación muestran que los Tsimane’ identifican un amplio número de indicadores locales de cambio ambiental. Dichos indicadores podrían ayudar a completar vacíos en los registros instrumentales de Cambio Ambiental Global. Esta tesis también muestra la existencia de una superposición entre el conocimiento indígena y los registros científicos de cambio climático, así como el papel instrumental que juegan las percepciones locales en propiciar respuestas colectivas para adaptarse al cambio. Sin embargo, los hallazgos de esta tesis también ilustran cómo el Cambio Ambiental Global supone un desafío para la capacidad de adaptación del Conocimiento Ambiental Local, al ensanchar la brecha temporal entre la velocidad de cambio del ecosistema y la velocidad de cambio del conocimiento indígena. La presente tesis aporta nuevos conocimientos a la discusión teórica sobre la efectividad del Conocimiento Ambiental Local en un contexto de cambios socio-ecológicos rápidos y sin precedentes. Los resultados de este trabajo destacan la importancia de trazar planes estratégicos para apoyar la adaptación del conocimiento indígena ante cambios ambientales cada vez más significativos. Esta investigación también muestra la importancia del Conocimiento Ambiental Local para informar y facilitar procesos de adaptación, particularmente en territorios indígenas. Dados estos resultados, abogo por la integración de los pueblos indígenas en los foros globales de políticas ambientales, así como el reconocimiento de sus sistemas de conocimiento en el ámbito científico. / Indigenous peoples are increasingly facing threats resulting from a changing global environment. Given the unprecedented rates of ongoing Global Environmental Change, there is scholarly debate on whether these threats might also undermine the adaptive capacity of indigenous knowledge. Due to its strategic position bridging the natural and social sciences, ethnoecology is well-placed to examine to what extent indigenous knowledge is adaptive in the face of rapid environmental changes. This PhD thesis is the result of a three-year interdisciplinary study aiming to understand the relations between Global Environmental Change and the Local Environmental Knowledge held by a native society in Bolivian Amazonia: the Tsimane’ hunter-gatherers. Facing rapidly changing social-ecological conditions and with the scientific discourse on anthropogenic global change still largely inaccessible to this group, the Tsimane’ constitute a suitable case study for casting light on how local perceptions of Global Environmental Change are captured in the social memory of indigenous peoples. The main argumentative line of this work is that Global Environmental Change has direct expressions at the local scale, including changes related to climate, the ecosystem and the availability of natural resources. In its four central chapters, this dissertation empirically investigates: (a) the potential use of indigenous knowledge for complementing scientific models assessing climate change; (b) the interplay between local observations of climate change and the uptake of scientific information; (c) the limits of the adaptive capacity of Local Environmental Knowledge in a context of rapid change; and (d) the role of local perceptions of change as drivers of adaptation to ecological shocks. This research involved qualitative and quantitative data collection during 15 months of fieldwork in 23 villages of the Tsimane’ Territory. I used a number of methods common to ethnoecological research, including participant observation, focus groups and systematic data collection. I specifically conducted semi-structured interviews on environmental change perceptions (n = 300 adults), knowledge tests to assess individual levels of Local Environmental Knowledge (n = 99) and a randomised controlled trial (n = 442). Additional climate and ecological data were sourced to obtain scientific estimates of environmental changes in the study area. The results of this dissertation show that the Tsimane’ identify a wide array of local indicators of environmental change. Such indicators could help to fill gaps in instrumental records of Global Environmental Change. This thesis also shows the existence of a significant overlap between Tsimane’ indigenous knowledge and scientific climate change records, as well as the instrumental role that local perceptions play in sparking collective responses for adapting to change. However, findings from this work also illustrate how Global Environmental Change challenges the adaptive capacity of Local Environmental Knowledge by widening the temporal gap between the rates of change in the ecosystem and the rates of change in the knowledge held by indigenous societies. This thesis brings new insights to the theoretical discussion on the effectiveness of Local Environmental Knowledge in the context of rapid and unprecedented social-ecological changes. Results of this work stress the importance of devising strategic plans to support the resilience of indigenous knowledge in the face of ever encroaching environmental changes. This study also shows the importance of building upon Local Environmental Knowledge for informing and facilitating adaptive processes, particularly in areas inhabited by indigenous groups. Given these findings, I argue for an integration of indigenous peoples in global environmental policy fora, as well as for the recognition of their knowledge systems in scientific scholarship.

The effect of ambient on photoluminescence (PL) from GaN was studied. We found that the PL intensity in vacuum was nearly four times higher than in air. The PL intensity also increased after etching the sample in Aqua Regia and BOE to remove the native oxide layer. After etching, the PL intensity was very stable in vacuum, but substantially degraded in air ambient. In HCl vapor (low pH), the PL intensity increased as compared to air ambient, while in NH3 vapor (high pH) it decreased. The quantum efficiency of the exciton and blue luminescence bands increased significantly with increasing excitation power density. This increase could not be explained by reduction of the depletion region width (field effect mechanism), but could be explained by changes in the nonradiative recombination rate at the surface (recombination mechanism). We therefore assume that in vacuum and acid vapor some surface species are desorbed or passivated, resulting in a decreased nonradiative recombination rate and increased PL intensity.

Conversion of biomass to energy does not contribute to the net increase of carbon dioxide in the environment, therefore the use of biomass waste as a clean and renewable fuel source is an attractive alternative to the use of fossil fuels. Biomass can be converted to energy via direct combustion or via thermo-chemical conversion to liquid or gas fuels. This study focuses on employing gasification technology to convert biomass waste to producer gas, which is then cleaned and fed as gaseous fuel into the gas turbine. Since the producer gases are usually low caloric values, the power plants performance under various operating conditions has not yet been proven. In this study, system performance calculations are conducted for a 5MWe and a 20MWe power plants using commercial software ThermoFlow. The power plants considered including simple gas turbine systems, steam turbine systems, combined cycle systems, and steam injection gas turbine systems (STIG) using the producer gas with low caloric values at approximately 30% and 15% of the natural gas heating value. The low caloric value fuels are shown to impose high back compressor pressure and increased power output due to increased fuel flow. Power augmentations under four different weather conditions are also calculated by employing gas turbine inlet fog cooling. Different capacity options for the heat recovery steam generator (HRSG) that provides the steam for STIG are analyzed.

Diante da contínua e crescente degradação das florestas e das dificuldades que a sociedade enfrenta no sentido de protegê-las e recuperá-las, este trabalho foi realizado com o intuito de contribuir para a valorização, proteção e implantação de árvores e florestas em propriedades rurais no município de Piracicaba/SP. Para tanto, efetuou-se uma pesquisa sobre a percepção que os produtores da Microbacia Tamandupá, tributária do Rio Corumbataí, possuem em relação ao elemento arbóreo e aos dispositivos de proteção ao mesmo, para que ao final, fossem propostas diretrizes para intervenções educacionais voltadas ao setor rural. Utilizando-se de contribuições conceituais e metodológicas advindas da educação, legislação e política ambiental, bem como das reflexões obtidas através de entrevistas com profissionais dessas áreas e da extensão rural, procurou-se construir um referencial teórico para analisar os dados de campo. Os resultados obtidos durante as entrevistas realizadas, foram analisados de forma qualitativa e quantitativa. Buscou-se também, realizar a estratificação dos dados, ou seja, a separação das respostas de acordo com características sócio-econômicas dos entrevistados para identificar padrões entre as mesmas. A intenção era avaliar o grau de percepção dos proprietários em relação ao elemento arbóreo e às leis, de modo a caracterizá-los de acordo com o grau de escolaridade, a idade, o tamanho das propriedades e o fato dos proprietários residirem ou não no campo. Não foi possível verificar grandes variações de respostas, que demonstrassem um pensamento comum para cada grupo, mas apontaram-se tendências que possibilitaram concluir, por exemplo, que os proprietários que residem no campo possuem maior identificação e afinidade em relação ao elemento arbóreo. Os dados obtidos contribuíram ainda, para a identificação de algumas frases bastante indicativas do pensamento, dos desejos e das opiniões dos agricultores, o que pode auxiliar na compreensão da realidade do setor e orientar trabalhos no sentido de instrumentalizar a tomada de decisões direcionadas à proteção ambiental. Conclui-se que o trato junto ao público alvo da presente pesquisa, é complexo e necessita de dedicação e continuidade. Deve-se sempre propiciar a participação dos mesmos em todas as etapas de trabalho, e observar métodos múltiplos de abordagem e intervenções. Outras formas de aproximação são também sugeridas, como por exemplo, as conversas informais, o contato via sindicato e a participação em eventos comuns aos produtores. Além disto, faz-se necessário o envolvimento de pessoas que podem influenciar na tomada de decisões (como caseiros, cônjuges, crianças, etc.). As intervenções educacionais devem contemplar procedimentos e conteúdos variados. Neste sentido, a promoção da sinergia entre educação, legislação e política, pode trazer grandes contribuições. A educação deve instigar o questionamento, o debate e as atitudes, enquanto que as leis podem representar a efetivação de acordos compactuados entre as pessoas e possibilitar o exercício da crítica, além de direcionar a criação de políticas efetivas de proteção ao meio ambiente. Sendo assim, vale ressaltar que a despeito das dificuldades existentes no processo de busca pela proteção e implementação do elemento arbóreo em propriedades rurais, existem perspectivas concretas de se reverter o quadro de degradação do ambiente que se observa na região e no mundo. / Due the continuum and increasing degradation of the forests and the difficulties that the society faces to protect and to recover them, this work was made to contribute for the valuation, protection and implantation of trees and forests in country properties of Piracicaba /SP. For in such a way, a research was effected on the perception that the producers of the Microbacia Tamandupá, of the River Corumbataí, have in relation to the arboreal element and the ways of protection, so that to the end, proposals lines of direction to educational interventions. Using of conceptual and methodological contributions from the education, legislation and ambient politics, as well as from the reflections gotten from interviews with professionals of these areas and of the agricultural extension, it was looked to construct a theoretical referential to analyze the field data. The results gotten during the interviews, had been analyzed in a qualitative and quantitative ways. One of the goals was to carry through the stratification of the data, or either, the separation of the results according to the sociological and economic characteristics of the interviewees, to identify standards among them. The idea was to evaluate the degree of perception of the owners in relation to the arboreal element and the laws, in order to characterize them according to the scholarship degree, the age, the size of the properties and the fact of the proprietors to inhabit or not in the field. It was not possible to verify great variations of answers, that demonstrated a common thought for each group, but had pointed trends that they make possible to conclude, for example, that the proprietors who inhabit in the field possess greater identification and affinity in relation to the arboreal element. Those data had still contributed, for the identification of some sufficiently indicative phrases of the thought, the desires and the opinions of the agriculturists, what can assist the understanding of the reality of the sector and guide works to the instrumentalization of taking decisions directed to the ambient protection. The treatment to the public of the present research, is complex and needs devotion and continuity. It must be propitiated the participation of same in all the stages of work, and always be observed multiple methods of boarding and interventions. Other forms of approach also are suggested, as for example, the informal colloquies, the contact through union and the participation in common events to the producers. Moreover, the involvement of people who can influence in the taking of decisions (as caretakers, partners, children, etc.) becomes necessary. The educational interventions must contemplate varied procedures and contents. In this direction, the promotion of the synergy between education, legislation and politics, can bring great contributions. The education must instigate the questioning, the debate and the attitudes, while the laws can represent the effectuation of agreements done between the people and make possible the exercise of the criticism, besides directing the creation of effective politics to protect the environment. In spite of the existing difficulties in the process of fetching the protection and implementation of the arboreal element in agricultural properties, there is a real perspective of reverting the picture of degradation of the environment that is seen in the region and in the world.