A Numerical Study of the Behaviour of Flexible Inserts in Laminar Channel Flow

The fluid-structure interactions between laminar channel-flow and pressure-loaded compliant-wall can lead to channel collapse and structural vibrations. Two-dimensional numerical simulations of fluid-conveying channels with flexible sections are conducted to investigate the steady-state and transient system behaviours. A non-dimensional scheme is developed to characterise and predict the maximum static wall deflection and the onset of self-excited oscillations. This work has applications in industrial and biomechanical engineering

The second generation of the CCCM system for in-vitro cardiac tissue engineering.

Cardiovascular disease is the leading cause of death worldwide. When a myocardial infarction occurs, scar tissue compensates the damaged myocardial tissue. This scar tissue increases the stiffness of the heart tissue, reduces the heart’s function, and finally leads to the heart failure (HF) disease. To have the tissue engraftment, in-vitro cardiac tissue should have the same properties as the native mature cardiac tissue. However, current in-vitro cell culture technologies fail to accurately recreate the in-vivo like mechanically physiological environment for in-vitro cardiac tissue culture, and therefore, fail to regenerate the in-vivo like mature cardiac tissue. Hence, a microfluidic cardiac cell culture model (CCCM) system was developed to better recreate the cellular environment and advance cardiac regeneration. CCCM system replicates the hemodynamic loading and unloading conditions occurring inside the left ventricle of a heart. With this system, different pressures of human heart conditions may be replicated for a variety of clinical and physiologic conditions. For proof-of-concept, embryonic chick cardiac cells with normal heart condition were applied. Compared to the tissue cultured in a static condition, tissues stimulated in the CCCM system achieved an in-vivo like cardiac matured phenotype, had higher proliferating rate, showed more maturity, and expressed more contractile proteins. These results demonstrated that the CCCM system can be used to study the behavior of cardiomyocytes in different mechanical heart conditions and to create mature cardiac tissue which will benefit cardiac tissue transplant for HF

Numerical modelling of fluid-structure interactions for fluid-induced instability in the upper airway

This study is concerned with fluid-structure interactions (FSI) involved in the human upper airway, in particular, those associated with snoring and obstructive sleep apnoea/hypopnoea syndrome (OSAHS). Further examining this area of interest, the goal of the current research is to contribute further understanding and enhance development of computational modelling, for retroglossal obstruction and palatal snoring. To that end, the investigation was divided into three major parts. Firstly, extending previous laminar, 2-D reduced Navier-Stokes model, an idealised 3-D computational model was constructed for studying retroglossal obstruction. A full Navier-Stokes solver in an Arbitrary Lagrangian-Eulerian (ALE) framework was coupled to a linear thin shell, where both laminar and turbulent flow was investigated. Numerical results showed increase flow-induced tongue replica deflection under turbulent conditions and demonstrated cross-flow pressures that may encourage side wall collapse. In the second part of the thesis, palatal snoring was further examined and its potential to detect retroglossal obstruction was proposed. In order to investigate this, flow-induced instability of a cantilever plate in an obstructed channel was modeled and a relationship between critical velocity and obstruction depth was established. Correlating the critical velocity with typical breathing flow curve, a time difference between palatal snoring episodes or onset of palatal snoring, may represent a key variable for non-invasive measurement of retroglossal obstruction severity. Further enhancement of the 2-D computational model by including contact was proposed using an immersed boundary method (IBM). This may represent a more complete model of palatal snoring by modelling pre- and post-contact response of unstable cantilever plate, which showed potential to capture more complicated palatal snoring signals. Finally, the third part of this thesis examined flow-induced instability of a soft palate in a 3-D realistic upper airway. To model this, a full 3-D Navier-Stokes solver under an ALE framework was coupled to a non-linear soft palate model. Appropriate soft palate properties were applied giving palatal snoring frequency within range of clinically measured values. Palatal flutter was observed at high flow rates, demonstrating irreversible transfer of flow energy to soft palate. This computational model may perhaps be exploited for future investigation of more accurate palatal snoring, necessary for developing non-invasive snoring signals for measurement or diagnosis of retroglossal obstruction

Index to NASA tech briefs, 1971

The entries are listed by category, subject, author, originating source, source number/Tech Brief number, and Tech Brief number/source number. There are 528 entries

Scale model testing of drogues for free drifting buoys

Instrumented model drogue tests were conducted in a ship model towing tank. The purpose of the tests was to observe and measure deployment and drag characteristics of such shapes as parachutes, crossed vanes, and window shades which may be employed in conjunction with free drifting buoys. Both Froude and Reynolds scaling laws were applied while scaling to full scale relative velocities of from 0 to 0.2 knots. A weighted window shade drogue is recommended because of its performance, high drag coefficient, simplicity, and low cost. Detailed theoretical performance curves are presented for parachutes, crossed vanes, and window shade drogues. Theoretical estimates of depth locking accuracy and buoy-induced dynamic loads pertinent to window shade drogues are presented as a design aid. An example of a window shade drogue design is presented

MICROBE-MINERAL RELATIONSHIPS AND BIOGENIC MINERAL TRANSFORMATIONS IN ACTIVELY VENTING DEEP-SEA HYDROTHERMAL SULFIDE CHIMNEYS

This dissertation uses a combination of microbiology, mineralogy, and geochemistry to understand dissimilatory iron reduction in hyperthermophilic archaea and the role and potential impact of these and other vent microorganisms within active deep-sea hydrothermal vent chimneys. The central objective of the dissertation is to determine if mineral composition and chimney type are among the primary determinants of microbial community composition and hyperthermophilic, dissimilatory iron reducer growth, in addition to other environmental factors such as nutrient availability, temperature, pH, and chlorinity. This is done using samples and organisms collected from the Endeavour Segment of the Juan de Fuca Ridge in the northeastern Pacific Ocean. The goals of this dissertation are: 1) to correlate microbial community compositions within three Endeavour hydrothermal chimneys with their mineral compositions using mineral spectroscopic techniques that have not been applied previously to hydrothermal chimneys, 2) to characterize the growth and Fe2+ production rates and constraints of two novel hyperthermophilic iron reducers isolated from Endeavour hydrothermal chimneys, and 3) to determine the mineral end-products of these iron reducers using mineral spectroscopic techniques that have not been applied previously with hyperthermophiles. This was first done by collecting three active hydrothermal chimneys and their associated high-temperature fluids from the Endeavour Segment, Juan de Fuca Ridge to evaluate the linkages among mineralogy, fluid chemistry, and microbial community composition within the chimneys. To identify mineralogy, Mössbauer, mid-infrared thermal emission, and VNIR spectroscopies were used for the first time on vent chimneys, in addition to thin-section petrography, x-ray diffraction (XRD) and elemental analyses. A chimney from the Bastille edifice was rich in Fe-sulfide and composed primarily of chalcopyrite, marcasite, sphalerite, and pyrrhotite (i.e., type I chimney) while chimneys from the Dante and Hot Harold edifices were rich in anhydrite (type II-III chimneys). The bulk emissivity and reflectance spectroscopies corroborated petrography, XRD, and elemental analyses, demonstrating the potential of these techniques for future shipboard analysis. The microbial community within the Bastille chimney was most closely related to mesophilic and thermophilic anaerobes of the deltaproteobacteria, especially sulfate reducers, and anaerobic hyperthermophilic archaea, while those within the Dante and Hot Harold chimneys were most closely related to mesophilic and thermophilic aerobes of the beta-, gamma- and epsilonproteobacteria. Numerical modeling of energy availability from redox reactions in vent fluids suggests that aerobic oxidation of sulfide and methane should be the predominant autotrophic microbial metabolisms at 25°C and 55°C and that anaerobic oxidation of methane should prevail at 80°C. While the microbial community compositions of all three chimneys show aerobic sulfide-oxidizing epsilonproteobacteria, the predominance of mesophilic sulfate reducers in the Bastille chimney suggests that type I chimneys may promote anaerobic metabolisms. The next two goals, namely characterizing the growth and Fe2+ production rates and constraints of two novel hyperthermophilic iron reducers isolated from Endeavour hydrothermal chimneys, and determining their mineral end-products using mineral spectroscopic techniques that have not been applied previously with hyperthermophiles, were carried out in parallel. Hyperthermophilic iron reducers are common in hydrothermal chimneys found along the Endeavour Segment in the northeastern Pacific Ocean based on culture-dependent estimates. However, information on the availability of Fe(III) (oxyhydr)oxides within these chimneys, the types of Fe(III) (oxyhydr)oxides utilized by the organisms, rates and environmental constraints of hyperthermophilic iron reduction, and mineral end products are needed to determine their biogeochemical significance and are addressed in this study. Thin-section petrography on the interior of a hydrothermal chimney from the Dante edifice at Endeavour showed a thin coat of Fe(III) (oxyhydr)oxide associated with amorphous silica on the exposed outer surfaces of pyrrhotite, sphalerite and chalcopyrite in pore spaces, along with anhydrite precipitation in the pores that is indicative of seawater ingress. The iron sulfide minerals were likely oxidized to Fe(III) (oxyhydr)oxide with increasing pH and Eh due to cooling and seawater exposure, providing reactants for bioreduction. Culture-dependent estimates of hyperthermophilic iron reducer abundances in this sample were 1,740 and 10 cells per gram (dry weight) of material from the outer surface and the marcasite-sphalerite-rich interior, respectively. Two hyperthermophilic iron reducers, Hyperthermus sp. Ro04 and Pyrodictium sp. Su06, were isolated from other active hydrothermal chimneys on the Endeavour Segment. Strain Ro04T grew on peptides, reduced poorly crystalline iron oxide to black ferromagnetic magnetite and produced acetate and minor amounts of ethanol. It did not grow on any other terminal electron acceptor or purely by fermentation. Strain Su06T also catabolized peptides but only when H2 was present and reduced poorly crystalline iron oxide to magnetite and nitrate to N2. They both grew between 82°C and 97°C (Topt 90-92°C) and pH 5.0 and 9.0, but strain Ro04T had a pH optimum of 8.0 while strain Su06T had a pH optimum of 5.0. 16S rRNA gene sequence similarity analysis indicated they are 98.4% identical to each other and are most closely related (\u3e98%) to Hyperthermus butylicus DSM 5456T, Pyrodictium abyssi DSM 6158T, Pyrodictium occultum DSM 2709T and Pyrodictium brockii DSM 2708T. The complete genome for Strain Su06 was obtained and genome comparisons done in silico between Strain Su06T against Hyperthermus butylicus and Pyrolobus fumarii, revealed that Strain Su06 is a novel species. Strain Ro04T had growth characteristics most similar to H. butylicus while strain Su06 was more similar to P. abyssi. However, the ability of the strains to reduce iron and their inability to reduce sulfur compounds clearly distinguished them from all of their closest relatives. Phylogenetic, genomic, and phenotypic data indicate that strain Ro04T is novel species of Hyperthermus and strain Su06T is a novel species of Pyrodictium. The name Hyperthermus hephaesti is proposed for strain Ro04T and Pyrodictium delaneyi is proposed for Su06T. Mössbauer spectroscopy of the iron oxides before and after growth demonstrated that both organisms form nanophase (nm) magnetite [Fe3O4] from laboratory-synthesized ferrihydrite [Fe10O14(OH)2] with no detectable mineral intermediates. They produced up to 40 mM Fe2+ in a growth-dependent manner while all abiotic and biotic controls produced \u3c 3 mM Fe2+. Hyperthermophilic iron reducers may have a growth advantage over other hyperthermophiles in hydrothermal systems that are mildly acidic where mineral weathering at elevated temperatures occurs

Design as a source of innovation to establish circular business models: how to prevent the single-use of plastic?

The current economy context moving from linear to circular models is establishing extraordinary parallelism between with design principles. Design solutions can support the transition of business to one which creates monetary and environmental benefits, increases resource efficiency, and maintains the value of products, materials, and waste. Recycling has been signaled as the main strategy for the plastics circular economy, but it presents itself as controversial since the industry’s demand is significantly lower than the recycled amount. The overall objective of this study is to explore when design principles, related to circular-economy concepts, become a source of innovation, in order to answer to the research question: “How can design be a source of innovation to transform businesses models accordingly to circular economy principles?”. The primary objective of this investigation is to develop our model resulting from reverse design and which is guided by the definition of a circular model strategy (System-Centered Circular-Design, SCCD) and the secondary objectives involve expanding the knowledge related to the various aspects of this model. A qualitative approach was chosen, to analyse the impact of the packaging design concepts along the definition of the business models and its circular loops. From the literature review ethnographic research is thus well suited to providing circular systems designers and companies decision-makers, with rich insights. WisePack design solution was selected to analyse the slowing and closing loop. The relevant insights to retain from the exploratory phase is that WisePack may have changed some of the assumptions made by the different stakeholders of the value chain. A SCCD toolbox is presented, to support designers identifying the requirements, constraints and opportunities of the circular approach. To prevent the single-use of plastic, scenarios were developed, taking into consideration users’ behaviour towards repair or reuse, taking-back products and their levels of engagement. Based on the results, it was concluded that the circular model strategy definition model (SCCD) is a valid tool. Confirming the primary and secondary objectives of this study. Showing that design principles, related to circular-economy concepts, become a source of innovation, and the SCCD model and toolbox, support the businesses models transformation.A relação entre o design e o aumento da competitividade económica pela criação de valor já tem sido abordada. Não obstante, no contexto atual em que a economia transita de modelos lineares para circulares está a estabelecer um paralelismo extraordinário entre os modelos económicos e os princípios de design. Novas soluções de design podem apoiar a transição de produtos, processos e modelos de negócios para um modelo que potencie a criação de benefícios monetários e ambientais,aumentea eficiência dos recursos pela minimização de desperdícios e recuperação de resíduos e, estimule de uma forma sustentável a cadeia de valor de produtos e serviços, matérias-primas e materiais. A reciclagem tem sido apontada como a principal estratégia para a economia circular do plástico, mas não deixa de ser um paradoxo, uma vez que a procura do setor é significativamente inferior à quantidade reciclada de acordo com a literatura analisada. O objetivo geral deste estudo, é explorar o modo como os princípios de design aplicados aosconceitos de economia circular fomentam a inovação e a transição de um modelo linear de gestão para um modelo económico regenerativo e restaurador. Donde, a seguinte pergunta de investigação: “Como pode o design ser uma fonte de inovação para transformar modelos de negócios de acordo com princípios da economia circular?”. O objetivo específico desta investigação é desenvolver o nosso modelo resultante do reverse design e que se pauta pela definição de uma estratégia de modelo circular (System-Centered Circular-Design, SCCD) e, em paralelo, aferir o conhecimento relacionado com as suas diferentes variáveis. Metodologicamente optou-se por uma abordagem qualitativa, para analisar o impacto dos conceitos de design de embalagens ao longo da definição dos modelos de negócio e dos seus ciclos. Neste âmbito, começou primeiramente, por se selecionar como caso de estudo, a solução de design WisePack para analisar o ciclo de desaceleração e fecho (slowing and closing loops). Esta solução de design para as embalagens plásticas, maximiza a funcionalidade do produto e do material, resultante do processo de design e manufatura.Apresentam-se os pressupostos dos modelos de negócios circulares WisePack, seguidos das entrevistas realizados às partes interessadas que orientam a análise do estudo de caso. O estudo de caso da WisePack descreve as questões mais importantes a ponderar na seleção dessas estratégias de design e define os modelos de negócios circulares num estágio inicial de design de produto e serviço. A natureza qualitativa da investigação visa obter informações de diferentes ângulos para compreender as restrições e os objetivos dos principais agentes envolvidos na cadeia de valor. Com base nos resultados das entrevistas semiestruturadas destacam-se quatro fatores com potencial de fomentar a transição de uma abordagem linear para uma circular, a saber: i) o design tem uma relação relevante com os seus modelos de negócio; ii) barreiras à implementação do design, podem impactar a geração de valor; iii) o design pode influenciar e alterar a apetência para a inovar; iv) a captura de valor do negócio está relacionada com a cultura de inovação nos modelos lineares de negócios em prática. De todo o modo, há a reter desta fase exploratória da investigação que a solução de design de embalagem apresentada durante as entrevistas - WisePack - pode ter alterado algumas das premissas feitas pelos representantes das diferentes partes interessadas da cadeia de valor. Posto isto, e com base na revisão da literatura e na experiência profissional, constatou-se que a investigação etnográfica revela ser adequada para fornecer aos designers de sistemas circulares e aos decisores das empresas, perceções valiosas. Em segundo lugar, e sob o intuito de testar o modelo System-Centered Circular-Design (SCCD) procurou-se compreender se o design pode condicionar os modelos de negócio das partes interessadas de toda a cadeia de valor. Daí, ser proposto um método com o objetivo de permitir que designers e gestores definam possíveis modelos de negócios circulares ajustados por princípios de design mais circulares - o SCCD. Expõe-se a ferramenta SCCD e da sua sistematização decorrem vários conceitos para a construção de novas e mais complexas colaborações na cadeia de valor. Essa relação no processo circular é definida em termos de atributos. Os atributos, características geométricas e funções são utilizados para facilitar a instrumentação deste processo inovador. Todas essas caracterizações de notação de SCCD parecem ser viáveis para a especificação do processo e fase de projeto. Este, suporta refinamento e abstração, tornando a estrutura SCCD fácil de entender e usar. As tabelas de diagnóstico do modelo, visam apoiar os designers na identificação dos requisitos, restrições e oportunidades da abordagem circular. No entanto, também orienta a comunicação entre o designer e os representantes de cada departamento envolvido no processo de transição do modelo de negócio linear para o circular. Com o objetivo de testar o modelo SCCD, cenários futuros foram desenvolvidos nesta investigação para poder ser estabelecida uma área de exploração e discussão sobre a adaptação do processo de design ao paradigma da economia circular. O foco tem por intuito facilitar a geração de ideias compartilhadas sobre a direção a tomar e as escolhas a fazer e promover soluções de design para a economia circular. Nesse sentido, é de extrema importância apresentar as tendências de contexto relevantes. Para o caso de prevenção do plástico de uso único, os cenários deverão levar em consideração as tendências futuras no comportamento dos utilizadores em relação ao reparo ou reutilização e devolução de produtos. Esses cenários também distinguem entre dois níveis diferentes de envolvimentodesses utilizadores. Como é expectável, algumas partes interessadas terão que atender a necessidades diferentes de outras em menos tempo, ou com diferentes níveis de risco e investimento. A finalizar, admite-se que novos testes piloto e trabalho de campo são recomendados para poderem ser validados os cenários futuros. Com efeito, e no decurso desta investigação, a complexidade da parceria e o investimento financeiro necessário, não possibilitaram a implementação do modelo. Daí que, se tenham construído duas narrativas a ilustrar os cenários futuros de prevenção à utilização do plástico de uso único, por meio do design. Por fim, e com base nos resultados, constata-se que o modelo de definição de estratégia de modelo circular (SCCD) constitui uma ferramenta válida na senda dos objetivos desta investigação. Pode assim concluir-se que, os princípios do design quando aplicados aos conceitos da economia circular, conseguem tornar-se fonte de inovação e, que o modelo SCCD consegue suportar a transição dos modelos de negócios

Numerical modelling of additive manufacturing process for stainless steel tension testing samples

Nowadays additive manufacturing (AM) technologies including 3D printing grow rapidly and they are expected to replace conventional subtractive manufacturing technologies to some extents. During a selective laser melting (SLM) process as one of popular AM technologies for metals, large amount of heats is required to melt metal powders, and this leads to distortions and/or shrinkages of additively manufactured parts. It is useful to predict the 3D printed parts to control unwanted distortions and shrinkages before their 3D printing. This study develops a two-phase numerical modelling and simulation process of AM process for 17-4PH stainless steel and it considers the importance of post-processing and the need for calibration to achieve a high-quality printing at the end. By using this proposed AM modelling and simulation process, optimal process parameters, material properties, and topology can be obtained to ensure a part 3D printed successfully

Transport of Enterococcus faecalis JH2-2 through sandy sediments: A combined experimental and modelling approach

The agricultural sector is one of the largest consumers of fresh water. With the ever-increasing problem of water scarcity, urbanization, over-population, and climate change, fresh water resources used by agriculture could be put to better use by redirecting it for drinking water purposes. In this context, many countries reuse treated urban waste water for irrigation, to overcome this problem. While this is a sustainable practice, the reuse of urban wastewater could facilitate the spread of pathogenic bacteria (or antibiotic resistant bacteria) in the subsoil region and consequently the groundwater. Since groundwater is one of the main sources of drinking water, the contaminants could pose a risk to human health. Furthermore, obtaining scientific data for emerging contaminants during water reuse is the need of the hour. The objective of this work is to build a mechanistic model that can aid in the development of large-scale risk assessment models; thus facilitating the setup of water reuse regulations for the relevant pathogenic organisms. In the present study, process based models were developed and evaluated using lab scale results. Then, the relative time scales of the processes are compared, and the relative importance of the various process studies are assessed. When assessing time scales of the processes, it is kept in mind that processes with relatively fast time scales can be approximated using equilibrium models, relatively slow processes can be neglected, and only the rate limiting processes can neither be neglected or further simplified in further model development. Therefore, an idea of the rate limiting processes assessed in lab scale can serve as important tools facilitating model simplification when evaluating larger scale models. A combined experimental and modelling approach has been used to study relevant transport and reactive processes during bacteria transport through sandy sediments. The mechanistic model contained transport processes which were implemented using the advective dispersive equation. An additional straining process was added using non-linear rate law. The biological processes of decay, respiration, attachment, and growth were expressed using linear rate laws. This mechanistic model was verified using data from fully water saturated, sediment packed lab-scale column experiments. Continuous injection of tracer, microspheres, and Enterococci (in water environments with and without dissolved oxygen and nutrients) was performed. The experiment was verified for three flow velocities (0.13, 0.08 and 0.02 cm/min), and the parameter values were compared for these flow velocities using dimensionless numbers. The linear rate coefficients were converted to a dimensionless form (Peclet and Damkoehler numbers respectively) to facilitate the comparison of processes across the various flow velocities. The results indicate that the processes of attachment and growth are flow dependent. Furthermore, in the presence of dissolved oxygen, attachment of bacteria to sediment was the most influential process. Sensitivity analysis showed that the parameters representing growth and respiration were influential, and care must be taken when using the results for field-scale experiments or models. These processes and parameters add new knowledge on the impact of urban wastewater reuse on the spread of pathogenic bacteria (especially resilient species like Enterococci), and emphasizes the importance of research in this area. Future work could focus on obtaining data from culture independent methods and extension of the model framework, and include (where necessary) non-linear rate laws. This will provide a critical pathway to developing a decision support framework for use by regulatory frameworks, policy makers, stakeholders, local and global environmental agencies, World Health Organization, or the United Nations.:List of Figures vii List of Tables xi List of Abbreviations xiii List of Symbols xv Summary xvii Zussamenfassung xix 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Broad Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Hypotheses and Research objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.3 Outline of the work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Concepts, terminologies, and methodology 7 2.1 Concepts and terminologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.2 The vadose zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.3 Porosity and pore models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.4 Darcy’s law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.2 Bacteria strain used and Processes Studied . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.2.1 Enterococcus faecalis JH2-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.2.2 Advection and Dispersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.2.3 Straining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.2.4 Microbial Decay and Respiration . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.2.5 Microbial Attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.2.6 Microbial Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.2.7 Dimensionless numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.3 Experimental design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2.4 Model setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3 Reactive-transport modelling of Enterococcus faecalis JH2-2 passage through water saturated sediment columns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.2 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.2.1 Experimental study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.2.2 Modeling and data analysis procedure. . . . . . . . . . . . . . . . . . . . . . . . 40 3.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 3.3.1 Determination of hydraulic and non-reactive transport parameters (experiments E1 and E2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 3.3.2 Determination of parameters related to the bacteria transport (E3 series) . . . 45 3.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.4.1 Physical processes (E1 and E2) . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.4.2 Biological Processes (E3 series) . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.5 Conclusions and Outlook. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 3.6 Supplementary material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 4 Determining the impact of flow velocities on reactive processes associated with Enterococcus faecalis JH2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 4.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 4.2 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 4.2.1 Experimental setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 4.2.2 Model Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 4.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 4.3.1 Tracer and microsphere experiments. . . . . . . . . . . . . . . . . . . . . . . . . 74 4.3.2 Bacteria experiments - comparison of processes. . . . . . . . . . . . . . . . . . . 75 4.4 Conclusions and Future work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 4.5 Supplementary material 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 4.6 Supplementary Material 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 5 Synthesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 5.1 Discussion and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 5.2 Critical review, pathways towards future work . . . . . . . . . . . . . . . . . . . . . . . 91 Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Note on the commencement of the doctoral procedure. . . . . . . . . . . . . . . . . . . . 107 Übereinstimmungserklärung. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 List of Publications and conference presentations. . . . . . . . . . . . . . . . . . . . . . . . 111 Acknowledgements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115Der Agrarsektor ist einer der größten Verbraucher von Süßwasser. Angesichts der zunehmenden Wasserknappheit, der Verstädterung, der Überbevölkerung und des Klimawandels könnten die von der Landwirtschaft genutzten Süßwasserressourcen besser genutzt werden, indem sie für Trinkwasserzwecke umgewidmet werden. In diesem Zusammenhang verwenden viele Länder aufbereitetes kommunales Abwasser für die Bewässerung, um dieses Problem zu lösen. Dies ist zwar eine nachhaltige Praxis, aber die Wiederverwendung von kommunalem Abwasser könnte die Ausbreitung pathogener Bakterien (oder antibiotikaresistenter Bakterien) im Untergrund und damit im Grundwasser fördern. Da das Grundwasser eine der Hauptquellen für Trinkwasser ist, könnten diese Schadstoffe eine Gefahr für die menschliche Gesundheit darstellen. Darüber hinaus ist es ein Gebot der Stunde, wissenschaftliche Daten über neu auftretende Verunreinigungen bei der Wasserwiederverwendung zu gewinnen. Ziel dieser Arbeit ist es, ein mechanistisches Modell zu erstellen, das bei der Entwicklung groß angelegter Risikobewertungsmodelle behilflich sein kann und somit die Aufstellung von Vorschriften für die Wiederverwendung von Wasser für die relevanten pathogenen Organismen erleichtert. In der vorliegenden Studie wurden prozessbasierte Modelle entwickelt und anhand von Ergebnissen im Labormaßstab bewertet. Anschließend werden die relativen Zeitskalen der Prozesse verglichen und die relative Bedeutung der verschiedenen Prozessstudien bewertet. Bei der Bewertung der Zeitskalen der Prozesse wird berücksichtigt, dass Prozesse mit relativ schnellen Zeitskalen durch Gleichgewichtsmodelle angenähert werden können, relativ langsame Prozesse können vernachlässigt werden, und nur die ratenbegrenzenden Prozesse dürfen in der weiteren Modellentwicklung weder vernachlässigt noch vereinfacht werden. Daher kann eine Vorstellung von den ratenbegrenzenden Prozessen, die im Labormaßstab bewertet werden, als wichtiges Instrument zur Vereinfachung des Modells bei der Bewertung von Modellen in größerem Maßstab dienen. Ein kombinierter experimenteller und modellierender Ansatz wurde verwendet, um relevante Transport- und reaktive Prozesse während des Bakterientransports durch sandige Sedimente zu untersuchen. Das mechanistische Modell enthielt Transportprozesse, die mit Hilfe der Advektions-Dispersions-Gleichung implementiert wurden. Ein zusätzlicher Filtrationsprozess ('straining') wurde mit Hilfe nichtlinearer Ratengesetze hinzugefügt. Die biologischen Prozesse des Zerfalls, der Atmung, der Anhaftung und des Wachstums wurden durch lineare Ratengesetze ausgedrückt. Dieses mechanistische Modell wurde anhand von Daten aus vollständig wassergesättigten, sedimentgefüllten Säulenexperimenten im Labormaßstab verifiziert. Kontinuierliche Injektion von Tracer, Mikrosphären und Enterokokken (in Wasserumgebungen mit und ohne gelösten Sauerstoff und Nährstoffe) wurde durchgeführt. Das Experiment wurde für drei Strömungsgeschwindigkeiten (0,13, 0,08 und 0,02 cm/min) verifiziert, und die Parameterwerte wurden für diese Strömungsgeschwindigkeiten anhand dimensionsloser Zahlen verglichen. Die linearen Ratengesetze wurden in eine dimensionslose Form umgewandelt (Peclet- bzw. Damköhler-Zahlen), um den Vergleich der Prozesse bei den verschiedenen Strömungsgeschwindigkeiten zu erleichtern. Die Konzentrationen wurden in regelmäßigen Abständen sowohl am Einlass als auch am Auslass der Kolonnen gemessen. Die überprüften Prozesse waren Advektion, Dispersion, Filtration, Zerfall, Atmung, Wachstum und Anhaftung. Der Versuch wurde für drei Strömungsgeschwindigkeiten (0,13, 0,08 und 0,02 cm/min) wiederholt, und die verifizierten Parameterwerte wurden für diese Strömungsgeschwindigkeiten verglichen. Die Ergebnisse zeigen, dass die Prozesse der Anhaftung und des Wachstums strömungsabhängig sind. Darüber hinaus war bei Vorhandensein von gelöstem Sauerstoff die Anhaftung der Bakterien an das Sediment der einflussreichste Prozess. Die Sensitivitätsanalyse zeigte, dass die Parameter, die das Wachstum und die Atmung repräsentieren, einflussreich sind, so dass bei der Verwendung der Ergebnisse für Experimente oder Modelle im Feldmaßstab Vorsicht geboten ist. Diese Prozesse und Parameter liefern neue Erkenntnisse über die Auswirkungen der Wiederverwendung von kommunalem Abwasser auf die Ausbreitung pathogener Bakterien (insbesondere widerstandsfähiger Arten wie Enterokokken) und unterstreichen die Bedeutung der Forschung in diesem Bereich. Zukünftige Arbeiten könnten sich auf die Gewinnung von Daten aus kulturunabhängigen Methoden und die Erweiterung des Modellrahmens konzentrieren und (wo nötig) nichtlineare Parameter einbeziehen. Dies wird einen entscheidenden Weg zur Entwicklung eines Rahmens für die Entscheidungsfindung darstellen, der von Regulierungsbehörden, politischen Entscheidungsträgern, Interessengruppen sowie lokalen und globalen Umweltbehörden, der Weltgesundheitsorganisation oder den Vereinten Nationen genutzt werden kann.:List of Figures vii List of Tables xi List of Abbreviations xiii List of Symbols xv Summary xvii Zussamenfassung xix 1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Broad Scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Hypotheses and Research objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.3 Outline of the work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Concepts, terminologies, and methodology 7 2.1 Concepts and terminologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1.2 The vadose zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.3 Porosity and pore models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1.4 Darcy’s law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.2 Bacteria strain used and Processes Studied . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.2.1 Enterococcus faecalis JH2-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.2.2 Advection and Dispersion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 2.2.3 Straining . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.2.4 Microbial Decay and Respiration . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.2.5 Microbial Attachment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.2.6 Microbial Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.2.7 Dimensionless numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.3 Experimental design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 2.4 Model setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3 Reactive-transport modelling of Enterococcus faecalis JH2-2 passage through water saturated sediment columns. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.2 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.2.1 Experimental study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.2.2 Modeling and data analysis procedure. . . . . . . . . . . . . . . . . . . . . . . . 40 3.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 3.3.1 Determination of hydraulic and non-reactive transport parameters (experiments E1 and E2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 3.3.2 Determination of parameters related to the bacteria transport (E3 series) . . . 45 3.4 Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.4.1 Physical processes (E1 and E2) . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.4.2 Biological Processes (E3 series) . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3.5 Conclusions and Outlook. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 3.6 Supplementary material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 4 Determining the impact of flow velocities on reactive processes associated with Enterococcus faecalis JH2-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 4.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 4.2 Materials and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 4.2.1 Experimental setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 4.2.2 Model Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 4.3 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 4.3.1 Tracer and microsphere experiments. . . . . . . . . . . . . . . . . . . . . . . . . 74 4.3.2 Bacteria experiments - comparison of processes. . . . . . . . . . . . . . . . . . . 75 4.4 Conclusions and Future work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 4.5 Supplementary material 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 4.6 Supplementary Material 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 5 Synthesis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 5.1 Discussion and conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 5.2 Critical review, pathways towards future work . . . . . . . . . . . . . . . . . . . . . . . 91 Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Note on the commencement of the doctoral procedure. . . . . . . . . . . . . . . . . . . . 107 Übereinstimmungserklärung. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 List of Publications and conference presentations. . . . . . . . . . . . . . . . . . . . . . . . 111 Acknowledgements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Orbital service module systems analysis study documentation. Volume 2: Technical report

Near term, cost effective concepts were defined to augment the power and duration capability offered to shuttle payload users. Feasible concept options that could evolve to provide free-flying power and other services to users in the 1984 time frame were also examined