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Full-Text Articles in Engineering

Investigating The Role Of Iron In The Photogranulation Phenomenon, Abeera Ayaz Ansari Dec 2020

Investigating The Role Of Iron In The Photogranulation Phenomenon, Abeera Ayaz Ansari

Doctoral Dissertations

Oxygenic photogranules (OPGs) are dense spherical microbial aggregates that are used for self-aerating wastewater treatment. Filamentous cyanobacteria are key granulating species, providing structural backbone and integrity in OPGs. Currently, the mechanisms for selecting filamentous cyanobacteria and their ability to form spherical OPGs are not well understood. Literature shows that iron (Fe) availability plays a significant role in the cyanobacterial growth and colony formation. Moreover, Fe availability is known to be dependent upon light, which is an essential growth substrate for the phototrophs. This research has investigated the role of Fe in the photogranulation phenomenon and the impact of light intensity …


Scaling Up The Oxygenic Photogranule (Opg) Wastewater Treatment Process, Joseph G. Gitau Jul 2020

Scaling Up The Oxygenic Photogranule (Opg) Wastewater Treatment Process, Joseph G. Gitau

Doctoral Dissertations

Photogranular biomass has yet to be utilized at large scale for wastewater treatment despite their potential to lower energy demand due to self-aerating capacity in addition to better process control compared to conventional technologies. An evaluation of critical driving factors affecting scaling up has yet to be undertaken. The current generation of oxygenic photogranules under hydrostatic conditions (a deviation from orthodox conditions creating other granules) limit seeding of larger reactors in time and scale. In addition, evaluating the photosynthetic productivity of granules which exist as closely commingled consortia with tightly coupled production and consumption processes, has yet to be undertaken. …


Characterization Of A Natural Clayey Silt And The Effects Of Sample Disturbance On Soil Behavior And Engineering Properties, Øyvind Blaker Jul 2020

Characterization Of A Natural Clayey Silt And The Effects Of Sample Disturbance On Soil Behavior And Engineering Properties, Øyvind Blaker

Doctoral Dissertations

Silts are considered a challenging material to deal with in geotechnical engineering design practice and there has been limited research on determining the engineering parameters of silts either by in situ or laboratory testing. This thesis presents results of an extensive research program that investigated the in situ and laboratory behavior of a low plasticity silt deposit at the Norwegian National Geotechnical Test Site at Halden, Norway. Results from multiple in situ tests including: piezocone, pore pressure dissipation, in situ pore pressure measurements, field vane, self-boring pressuremeter and screw plate load tests were synthesized to characterize the Halden silt. Soil …


Synthesis And Characterization Of Geopolymers Cast And Cured In Saline Water And The Potential Application In Construction Engineering, Xiaonan Ge Jul 2020

Synthesis And Characterization Of Geopolymers Cast And Cured In Saline Water And The Potential Application In Construction Engineering, Xiaonan Ge

Doctoral Dissertations

The characteristics of underwater cast and cured geopolymers were experimentally studied to understand the interactions between geopolymer slurry and curing saline water and pertinent effects on its strength development. Geopolymers were synthesized from a mixture of Class C fly ash and metakaolin, and the influences of two different Si/Al molar ratios (1.78 and 2.00) and four different Na/Al (0.67, 0.80, 0.84, and 1.00) molar ratios were investigated, respectively. The geopolymer slurry was prepared and then cast into porous molds, followed by immediately submerged into 0, 15, and 35 ppt saline solutions (prepared with commercial seasalts) for 28-days’ curing in ambient …


Nanoindentation Characterization Of Elastic Properties Of Shales And Swelling Clay Minerals, Shengmin Luo Mar 2020

Nanoindentation Characterization Of Elastic Properties Of Shales And Swelling Clay Minerals, Shengmin Luo

Doctoral Dissertations

Oil and gas shales are a class of multiscale, multiphase, hybrid inorganic-organic sedimentary rocks that consist of a generally uniform, preferentially oriented clay matrix with randomly embedded silt and sand particles as solid inclusions. A thorough understanding of the mechanical properties of shales is crucial for the exploration and production of oil and gas in the unconventional shale reservoirs, but it can be a challenging task due to their nature of compositional heterogeneity and microstructural anisotropy. In efforts to better characterize the mechanical properties of shales across different length scales and to fundamentally understand the laws of upscaling from individual …


Computational Modeling Of Laminated Veneer Bamboo (Lvb) Dowel Joints, Niloufar Khoshbakht Feb 2020

Computational Modeling Of Laminated Veneer Bamboo (Lvb) Dowel Joints, Niloufar Khoshbakht

Doctoral Dissertations

Laminated veneer bamboo (LVB) is a sustainable building material that has been gaining interest in the construction industry of late. As a relatively new product, little is known about its connection performance, specifically, its failure behavior in dowel type joints and possible similarities it may have to engineered wood products in terms of failure mechanisms. Research is needed to aid in the understanding of LVB dowel connection failure behavior and to quantify the failure mechanism and key factors associated with LVB dowel connection strength. Modeling, as conducted in this research, is a valuable tool to help devise safe standards and …