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Enhancing Energy Recoverability of Municipal WastewaterSnider-Nevin, Jeffrey 09 May 2013 (has links)
Wastewater contains many valuable constituents, including phosphorus, nitrogen and more energy than what is required to treat it. This, combined with increasingly more stringent effluent requirements and the desire for water reuse, creates a demand for a system capable of both nutrient and energy recovery. The main objective was to develop a new wastewater treatment process configuration capable of maximizing energy recovery while enhancing biological phosphorus removal. Three pilot membrane bioreactors were operated at SRTs ranging from 2 days to 8 days to evaluate membrane fouling, treatment performance, sludge production and sludge settleability. The results showed high organics removal and near complete nitrification at all SRTs. Membrane fouling was highest at lower SRTs. The collected data were then used to calibrate a series of model configurations. The best configuration consisted of two sludge systems in series, with a short SRT anaerobic-aerobic first stage and an extended SRT pre-anoxic second stage. / Canadian Water Network
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Bringing nature to consciousness in peace and conflict studies through a phenomenological analysis of veterans’ narratives of nature and recoveryWestlund, Stephanie 13 December 2012 (has links)
Peace and conflict studies arose as a response to the human experience of violence, with an intention towards finding possibilities for nonviolent ways of relating. These possibilities, however, tend to be preoccupied with social conflict, reconciliation, and recovery as taking place solely within the realm of human beings, thereby creating an ontology that renders nature silent. This thesis asks why it is so difficult to attend to natural contexts and the more-than-human world in peace and conflict studies. This research suggests that the shift in experience that comes through connection with nature opens possibilities for peacebuilding and recovery from conflict. Thus, while it explores responses to experiences of violence, this thesis also works to articulate an understanding of how conflict and peacebuilding take place within a shared, interconnected and interdependent global ecosystem.
The core of this inquiry is experience-centred narrative research within the phenomenological interpretive framework provided by Maurice Merleau-Ponty. This research explores the personal experience stories of veterans suffering from stress and post-traumatic distress from their military training and combat exposure. All of the veterans regard their personal recovery from stress and traumatic experiences as intimately tied to their nature experiences. These experiences are further illuminated by supporting interviews, personal narrative interludes, other stories from the edges of violence, and theories and praxis in ecology, ecopsychology, cognitive science, and neuroscience.
Through exploring themes of sensory experience, safety, sense of purpose, relationships, basic needs, and regained humanity, this research culminates in the remembrance that as human beings, we are nature, and the insight that it is our (human) nature that impels and enables us to reach out and relate with others and with the more-than-human world. This central insight holds profound implications for peace and conflict studies, which focuses on peacebuilding through recognition of common humanity and conflict transformation through changed relationships. The thesis concludes by exploring possibilities and implications for bringing nature to consciousness in peace and conflict studies and for revising theoretical and practical frameworks to re-embed peace and conflict studies in the everyday world—the world beyond the boardroom or negotiating table, and the world that sustains all life on earth.
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Aquifer storage and recovery in saline aquifersChen, Yiming 27 August 2014 (has links)
Aquifer storage and recovery (ASR) is a particular scheme of artificial recharge of groundwater by injecting fresh water into aquifers and subsequently recovering the stored water during times of peak demand or extended drought. In the era of combating climate change, ASR, as an effective means for water reuse and sustainable management of water resources in concert with the natural environment, represents a huge opportunity for climate change adaptation to mitigate water availability stress.The success of an ASR scheme is quantified by the recovery efficiency (RE), defined as the volume of stored water that can be recovered for supply purposes divided by the total volume injected. It is not uncommon that RE may be significantly lower than 100% because of the water quality changes as a consequence of the mixing between the injected water and native groundwater and the interaction between injected water and soil. Thus, the key of a successful ASR scheme is (1) to select appropriate aquifers and (2) to design optimal operational processes to build up a bubble of injected water with minimized negative impact from such mixing and interaction.
To achieve this, this thesis develops an integrated knowledge base with sound interdisciplinary science and understanding of the mixing processes under operational ASR management in aquifers with various hydrogeological conditions. Analytical and numerical modeling are conducted to improve the scientific understanding of mixing processes involved in ASR schemes and to provide specific technical guidance for improving ASR efficiency under complex hydrogeological conditions. (1) An efficient approach is developed to analytically evaluate solute transport in a horizontal radial flow field with a multistep pumping and examine the ASR performance in homogeneous, isotropic aquifer with advective and dispersive transport processes. (2) Numerical and analytical studies are conducted to investigate the efficiency of an ASR system in dual-domain aquifers with mass transfer limitations under various hydrogeological and operational conditions. Simple and effective relationships between transport parameters and ASR operational parameters are derived to quantify the effectiveness and ascertain the potential of ASR systems with mass transfer limitations.(3) Effects of hydrogeological and operational parameters on ASR efficiency are assessed in homogeneous/stratified, isotropic/anisotropic coastal aquifers. Effects of transverse dispersion are particularly investigated in such aquifers.(4) Finally, we test and study an innovative ASR scheme for improving the RE in brackish aquifers: injection through a fully-penetrated well and recovery through a partially-penetrated well.
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Bringing nature to consciousness in peace and conflict studies through a phenomenological analysis of veterans’ narratives of nature and recoveryWestlund, Stephanie 13 December 2012 (has links)
Peace and conflict studies arose as a response to the human experience of violence, with an intention towards finding possibilities for nonviolent ways of relating. These possibilities, however, tend to be preoccupied with social conflict, reconciliation, and recovery as taking place solely within the realm of human beings, thereby creating an ontology that renders nature silent. This thesis asks why it is so difficult to attend to natural contexts and the more-than-human world in peace and conflict studies. This research suggests that the shift in experience that comes through connection with nature opens possibilities for peacebuilding and recovery from conflict. Thus, while it explores responses to experiences of violence, this thesis also works to articulate an understanding of how conflict and peacebuilding take place within a shared, interconnected and interdependent global ecosystem.
The core of this inquiry is experience-centred narrative research within the phenomenological interpretive framework provided by Maurice Merleau-Ponty. This research explores the personal experience stories of veterans suffering from stress and post-traumatic distress from their military training and combat exposure. All of the veterans regard their personal recovery from stress and traumatic experiences as intimately tied to their nature experiences. These experiences are further illuminated by supporting interviews, personal narrative interludes, other stories from the edges of violence, and theories and praxis in ecology, ecopsychology, cognitive science, and neuroscience.
Through exploring themes of sensory experience, safety, sense of purpose, relationships, basic needs, and regained humanity, this research culminates in the remembrance that as human beings, we are nature, and the insight that it is our (human) nature that impels and enables us to reach out and relate with others and with the more-than-human world. This central insight holds profound implications for peace and conflict studies, which focuses on peacebuilding through recognition of common humanity and conflict transformation through changed relationships. The thesis concludes by exploring possibilities and implications for bringing nature to consciousness in peace and conflict studies and for revising theoretical and practical frameworks to re-embed peace and conflict studies in the everyday world—the world beyond the boardroom or negotiating table, and the world that sustains all life on earth.
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Microbial enhanced oil recovery : a pore-scale investigation of interfacial interactionsArmstrong, Ryan T. 06 January 2012 (has links)
Current oil production technologies recover only about one‐third to one‐half of the oil
originally present in an oil reservoir. Given current oil prices, even a modest increase in oil recovery efficiency is fiscally attractive. One novel approach to increase oil recovery
efficiency is a process called microbial enhanced oil recovery (MEOR), where microorganisms
are either used as a clogging agent to redirect flow or to produce biosurfactant that reduces
interfacial tension. This dissertation aims to understand the MEOR pore‐scale mechanisms
relevant to oil recovery by taking a two‐fold approach where transparent 2‐dimensional
micromodel experiments imaged with stereo microscopy and 3‐dimensional column
experiments imaged with x‐ray computed microtomography (CMT) are utilized. Micromodel
experiments allow for direct visualization of the biological phase (i.e. biofilm), however, only 2‐dimensional information is provided. Conversely, CMT experiments provide 3‐dimensional
pore‐scale information, but lack the ability to image the biological phase. With this two‐fold
approach, it is possible to distinguish multiple fluid interfaces, quantify fluid phase
saturations, measure oil blob size distributions, and visualize the biological phase.
Furthermore, a method to measure interfacial curvature from 3‐dimensional images is
developed, providing researchers a new perspective from which to study multiphase flow
experiments. Overall, the presented research utilizes pore‐scale imaging techniques to study
the interfacial interactions occurring during MEOR in an effort to better explain the physics,
and thus, increase the efficacy of MEOR. / Graduation date: 2012
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Preparatory strategies for optimising an all-out sprint effortMohd Sani Madon January 2007 (has links)
[Truncated abstract] The inclusion of a warm-up in the form of prior exercise (PE) is generally advocated as a preparatory strategy of choice to improve sprint performance. Although there is evidence that both increasing muscle temperature and mobilising the cardiorespiratory system prior to exercise contribute largely to the benefit of PE on sprint performance, their relative importance is unknown. Another important question relates to situations where an athlete has to engage in a sprint shortly after one or several earlier sprints. Under these conditions, is engaging in mild exercise also the most effective preparatory strategy to adopt prior to sprinting when performed after a previous sprint(s)? It was the primary aim of this thesis to address these questions. Firstly, we hypothesised that there is a temporal shift in the mechanisms responsible for the effect of PE on power output during a maximal sprint effort, with temperature-dependent mechanisms playing a more important role at the onset of the sprint and mobilisation of the cardiorespiratory system playing a more important role later. To test this hypothesis, we compared the responses of a 30-s sprint to different PE protocols designed to control for either muscle temperature or pre-exercise VO2. ... A group of trained athletes was subjected to four consecutive bouts of 30-s sprint, each separated by 20 min of either active recovery at 40% VO2 peak or passive recovery. Our results show that PP, MP-20 and MP-10 did not fall between the first and last sprints, and were not affected by active recovery. In contrast, we found that MP10 and MP30 decrease significantly between the first and last sprint of the passive recovery trial, but not when active recovery is performed between consecutive sprints. Finally, this study also showed that the fall in mean power associated with repeated 30-s sprints in the passive recovery trial resulted primarily from a fall in early, but not late power output. These findings show that the early and late mean power output of repeated sprints respond differently to active and passive recovery, with the decrease in total mean power with repeated 30-s sprints resulting primarily from a fall in early as opposed to either late power output or peak power, thus highlighting the benefit of active recovery as a favourable preparatory strategy for the performance of repeated sprints of short (<10s) or longer duration (<30s), but not for repeated peak power.
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Reservoir simulation study for the South Slattery FieldWang, Linna. January 2007 (has links)
Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on July 26, 2010). Includes bibliographical references (p. 93-96).
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[en] SYNCHRONIZATION IN COMMUNICATION SYSTEMS / [pt] SINCRONIZAÇÃO EM SISTEMAS DE TELECOMUNICAÇÕESMARCELO PEIXOTO RIBEIRO 09 November 2006 (has links)
[pt] O presente texto aborda aspectos do problema de
sincronização em sistemas de telecomunicações, com
enfoque
nas funções de demodulação síncrona, regeneração,
multiplexação/demultiplexação (TDM) e comutação (digital).
São tratados os métodos de obtenção de referência de
portadora e de referência de relógio, os recursos de
malha de amarração de fase (PLL) e de memória elástica.
O objetivo final consiste na descrição dos métodos de
sincronização de rede, nas modalidades plesiócrona (e
plesiócrona com justificação), mestre-escravo e
sincronização mútua.
As subredes de sincronização são analisadas em termos de
topologia, segurança, determinação de freqüência e fases
de operação e de compensação de defasagens na transmissão.
A apresentação é feita em termos de um texto didático
para
a descrição dos problemas e de suas soluções. / [en] This text deals with aspects of synchronization in
telecommunication systems, with emphasis on the
operational functions of synchronous demodulation, signal
regeneration, multiplexing/demultiplexing (TDM) and
digital switching.
The methods of carrier recovery, clock recovery,
phase locked loop and elastic store are presented.
The final goal consists on the description of network
synchronization methods, in the plesiochronous (and
plesiochronous with justification), master-slave and
mutual synchronization modalities.
The synchronization subnetworks are analised in
terms of topology, safety, operation frequency and phases,
and transmission phase delay compensation.
The presentation is made in a didactical way,
describing the problems and their possible solutions.
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Investigating the Efficacy of Novel TrkB Agonists to Augment Stroke RecoveryJanuary 2013 (has links)
abstract: Stroke remains the leading cause of adult disability in developed countries. Most survivors live with residual motor impairments that severely diminish independence and quality of life. After stroke, the only accepted treatment for these patients is motor rehabilitation. However, the amount and kind of rehabilitation required to induce clinically significant improvements in motor function is rarely given due to the constraints of our current health care system. Research reported in this dissertation contributes towards developing adjuvant therapies that may augment the impact of motor rehabilitation and improve functional outcome. These studies have demonstrated reorganization of maps within motor cortex as a function of experience in both healthy and brain-injured animals by using intracortical microstimulation technique. Furthermore, synaptic plasticity has been identified as a key neural mechanism in directing motor map plasticity, evidenced by restoration of movement representations within the spared cortical tissue accompanied by increase in synapse number translating into motor improvement after stroke. There is increasing evidence that brain-derived neurotrophic factor (BDNF) modulates synaptic and morphological plasticity in the developing and mature nervous system. Unfortunately, BDNF itself is a poor candidate because of its short half-life, low penetration through the blood brain barrier, and activating multiple receptor units, p75 and TrkB on the neuronal membrane. In order to circumvent this problem efficacy of two recently developed novel TrkB agonists, LM22A-4 and 7,8-dihydroxyflavone, that actively penetrate the blood brain barrier and enhance functional recovery. Findings from these dissertation studies indicate that administration of these pharmacological compounds, accompanied by motor rehabilitation provide a powerful therapeutic tool for stroke recovery. / Dissertation/Thesis / Ph.D. Neuroscience 2013
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Estudo experimental da co-injeção de vapor e gases efluentes de combustão na recuperação melhorada de óleo pesado / Experimental study of steam and flue gas co-injection in improved heavy oil recoveryMonte-Mor, Lucas Soares, 1988- 23 August 2018 (has links)
Orientador: Osvair Vidal Trevisan / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica e Instituto de Geociências / Made available in DSpace on 2018-08-23T06:58:59Z (GMT). No. of bitstreams: 1
Monte-Mor_LucasSoares_M.pdf: 24137724 bytes, checksum: e77cff06c62fba11b775f82eba0fb083 (MD5)
Previous issue date: 2013 / Resumo: A injeção de vapor produzido na superfície é o método de recuperação avançada de petróleo mais utilizado para produção de óleo pesado no mundo. No entanto, há grandes limitações no uso no método devido a perdas de calor quando os reservatórios são profundos e no caso de campos offshore. Os geradores de fundo de poço ("Downhole steam generators, DHSG") são uma nova tecnologia que abre caminho para a recuperação de óleo pesado de reservatórios profundos, campos offshore e locais extremamente frios. Os DHSGs eliminam a necessidade dos sistemas de distribuição e geração de vapor na superfície como as linhas de escoamento de vapor. A saída de um DHSG entrega uma mistura de vapor e gases efluentes de combustão. No presente trabalho, um estudo experimental na célula linear de injeção foi desenvolvido para compreender melhor como a injeção combinada de vapor e gases efluentes de combustão contribui no processo de recuperação e para a possível redução na quantidade de vapor injetado. O estudo experimental foi realizado num aparato construído e desenvolvido na Unicamp para a injeção contínua de vapor puro ou vapor combinado com outro fluido. Todo o estudo foi realizado em escala de laboratório utilizando óleo proveniente da bacia Potiguar e do Espírito Santo. Nos experimentos, vapor foi injetado em vazões de 5 ml/min quando puro e de 4,5 ml/min quando em co-injeção com gases efluentes de combustão. As vazões de gás variaram entre 150 e 800 ml/min. Os resultados encontrados mostram que: 1) Há uma aceleração na produção de óleo quando na presença do gás co-injetado com vapor, se comparado com a injeção de vapor puro; 2) O gás ajuda a manter a pressão atrás da frente de vapor mais estável; 3) A melhoria da razão vapor/óleo mostra que a co-injeção do gás efluente de combustão é benéfica para substituir certa quantidade de vapor; 4) Os fatores de recuperação quando se utiliza o gás são maiores do que quando se utiliza apenas vapor puro, havendo uma tendência de aumento do fator de recuperação com o aumento do volume de gás injetado e 5) Ocorre uma variação na qualidade do óleo produzido ao longo do histórico de recuperação com a co-injeção / Abstract: The surface steam injection is the most common enhanced oil recovery (EOR) process used in heavy oil production. Nevertheless, there are limitations due to the heat loss for deep reservoirs and for offshore fields. Downhole steam generators (DHSG) are a new technology that opens new pathways for recovery of heavy oil from deep reservoirs, offshore fields and extreme cold regions. DHSGs eliminate the need for surface steam distribution systems, for flowlines and wellbore steam strings. The outflow of DHSG generators are a mixture of steam and flue gas. In the present work, an experimental study was developed in a linear steam injection cell to better understand how the injection of steam combined with flue gas contributes to the recovery process and to the possible reduction in the required amount of steam injected. The experimental apparatus used in this study was designed and built at Unicamp for flooding of steam or steam combined with other fluid. The entire study was conducted at the lab scale with a heavy oil originated from the Potiguar Basin and from the Espírito Santo Basin. In the experiments, steam was injected at flow rates of 5 ml / min when pure and 4.5 ml / min when co-injected with flue gas. The gas flowrate varied between 150 and 800 ml / min. The results show that: 1) the coinjection of steam with flue gas accelerates the start of oil production when compared with steam injection alone; 2) The gas helps to keep the pressure behind the front and make it more stable; 3) The improvement on the steam/oil ratio shows that co-injection of steam with flue gas is beneficial to replace a significant amount of steam; 4) Recovery factors when co-injecting gas is greater than when using pure steam, with an increasing trend for the recovery factor when the volume of gas injected increases and 5) a favorable variation occurs in the quality of the oil produced during the recovery history with co-injection / Mestrado / Reservatórios e Gestão / Mestre em Ciências e Engenharia de Petróleo
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