Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"flux partitioning"”.
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Carbon fluxes of an extensive meadow and attempts for flux partitioning
… into shoots, roots, soil and respiration fluxes on drought and normal plots in a stable isotope pulse labeling experiment. An increase of carbon allocation by 6.2% to below ground pools as soil and roots and a reduction of shoot respiration by 8.5% due to spring drought were found. Gaining …
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Experimental study of heat flux partitioning in pressurized subcooled flow boiling
… of subcooled flow boiling and the critical heat flux (CHF) is of the utmost importance for both safety and profitability of pressurized water nuclear reactors since they are major factors in the determination of the reactor power rating. Motivated by the emergence of a new wall boiling model by …
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Development and assessment of a physics-based model for subcooled flow boiling with application to CFD
… designs. A second-generation mechanistic heat flux partitioning framework developed in our group provides an enhanced physical description of flow boiling.
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CO2 and Isotope Flux Measurements above a Spruce Forest
… and seasonal variation in the governing gross flux components of assimilation, i.e. photosynthetic uptake of CO2, and respiration. In this dissertation, a set of criteria is suggested for the identification of high quality NEE data. They are applied to data obtained above a spruce forest in the …
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Experimental Investigation of Subcooled Flow Boiling and CHF at Prototypical Pressures of Light Water Reactors
… frequency, wait and growth times), heat flux partitioning and departure from nucleate boiling. The results reveal that in high pressure flow boiling bubbles depart by sliding immediately after nucleation, with no adhesion force holding a bubble in place. Drag, buoyancy and inertia were …
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Infrared Thermometry Analysis of Surface Effects in Subcooled and Saturated Boiling of Water
… instrumental in enhancing the accuracy of heat flux partitioning methods. The enriched understanding and insights are anticipated to be integral for developing more refined multiphase computational fluid dynamics codes, crucial for designing efficient heat-dissipating mechanisms in applications …
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Carbon fluxes at an upland blanket bog in the north Pennines
… were made of all of the key gaseous carbon fluxes, including the net CO2 flux, the soil CO2 flux and emissions as methane. A flux partitioning model was utilised to separate the net CO2 flux into its component parts. Values for the fluvial carbon losses from the site were taken from the …
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Advancing State-of-the-art Multiphase CFD Modeling for PWR Applications
… test cases at various flow conditions, heat flux, inlet subcooling, and pressure have been used in this systematic validation. This work leverages advancements in momentum closures to perform a systematic assessment of wall boiling representation by evaluating heat flux partitioning …
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Investigation of Separate Effects of Surface Condition on Subcooled Flow Boiling Heat Transfer
… reactor power is limited by the critical heat flux (CHF), at which the boiling crisis occurs. Understanding the mechanisms that trigger this boiling crisis and predicting the CHF limit is key to the safety and efficiency of nuclear reactors. The CHF limit depends on cladding material, …
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Terrestrial Water Storage Change Over Dryland Regions Using Observational Data and Model Simulations
… terrestrial water storage (TWS) changes and flux partitioning patterns over global-, regional-, and catchment-scale drylands. The first study mainly evaluates TWS changes over global drylands from April 2002 to January 2017 using satellite observations. My collaborators and I find that water …
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Synthesis of CRUD and its effects on pool and subcooled flow boiling
… may have large effects on critical heat flux (CHF) and heat transfer coefficient (HTC). An investigation of such effects was conducted as part of the CASL project by creating well-defined and characterized synthetic CRUD with parameters representative of reactor CRUD on indium tin …
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High-Resolution Experimental Measurements and Mechanistic Modelling of Saturated Cryogenic Pool Boiling Heat Transfer
… poor prediction accuracy of the boiling heat flux in most applications, but also miss critical boiling characteristics, e.g., the amount of vapor produced. This thesis proposes a fully closed formulation of a mechanistic boiling model adapted to saturated cryogenic pool boiling. The model …
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Geometric and numerical optimisation of single- and two-phase convective heat transfer in microchannel heat sinks
… required for the present and future high heat flux applications because natural and forced air convection and many other cooling methods employing liquid coolants cannot meet up with the challenges. More transistors are added to the surfaces of electronic chips to increase the capacity of …
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Simulating organization of convective cloud fields and interactions with the surface
… layer is forced by the amount of surface fluxes from below. Conversely, landscape patterns and land-cover heterogeneity may equally give rise to focused regions for deep convection triggering, in particular when patch sizes exceed 10 km. Since the convective boundary layer has a mediating …
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Impacts of model-data uncertainties on biogeophysical-biogeochemical interactions in a land surface model (with an emphasis on the northern high-latitude regions)
… Model (ISAM), at spatial scales ranging from flux tower sites to the global land surface in order to explore how the modeling uncertainties translate from site to regional to global scales. I studied the impacts from three key factors that can largely contribute of modeling uncertainties in …
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Data-led methods for the analysis and interpretation of eddy covariance observations
… analysis and interpretation of net canopy CO₂ flux observations. Given the limited knowledge about the underlying real system, the evaluation of the derived models with synthetic canopy exchange data is introduced as a standard procedure prior to any real data employment. The derived data-led …
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Quantification of the Fire Thermal Boundary Condition
… surface was quantified with a hybrid heat flux gage. Methods were developed to determine the net heat flux through the gage, incident heat flux, cold surface heat flux, convective heat transfer coefficient, adiabatic surface temperature, and the separated components of radiative and …