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Full-Text Articles in Engineering

Sudden Increase And Regrowth Of Fecal Coliforms And Escherichia Coli In Wastewater Biosolids After High Solids Centrifugation, Gordon G. Araujo May 2012

Sudden Increase And Regrowth Of Fecal Coliforms And Escherichia Coli In Wastewater Biosolids After High Solids Centrifugation, Gordon G. Araujo

Master’s Theses

Treatment plants that operate either thermophilic or mesophilic anaerobic digesters with centrifugal dewatering processes have consistently observed densities of fecal coliform and Escherichia coli, both indicator bacteria, that decrease during digestion but then increase after dewatering and storage. The increases have been characterized as two separate phenomena to explain this observation: 1) “Sudden Increase,” or SI, which is defined as the increase that occurs immediately after dewatering and 2) “regrowth,” which is defined as an increase during storage of cake samples over a period of hours or days. The SI observation appears to be more prevalent with biosolids that are …


Monitoring And Modeling Of The Hydraulic And Sediment Processes At In-Stream Restoration Structures In The Vicinity Of A Bridge Crossing, Brian P. Schultz May 2012

Monitoring And Modeling Of The Hydraulic And Sediment Processes At In-Stream Restoration Structures In The Vicinity Of A Bridge Crossing, Brian P. Schultz

Master’s Theses

The long-term performance of infrastructure depends on reliable and sustainable designs. Many of Pennsylvania’s streams experience sediment transport problems that increase maintenance costs and lower structural integrity of bridge crossings. A stream restoration project is one common mitigation measure used to correct such problems at bridge crossings. Specifically, in an attempt to alleviate aggradation problems with the Old Route 15 Bridge crossing on White Deer Creek, in White Deer, PA, two in-stream structures (rock cross vanes) and several bank stabilization features were installed along with a complete channel redevelopment. The objectives of this research were to characterize the hydraulic and …


Investigation Of Human-Structure Interaction Through Experimental And Analytical Studies, Nicholas Noss Apr 2012

Investigation Of Human-Structure Interaction Through Experimental And Analytical Studies, Nicholas Noss

Master’s Theses

Vibration serviceability is a widely recognized design criterion for assembly-type structures, such as stadiums, that are likely subjected to rhythmic human-induced excitation. Human-induced excitation of a structure occurs from the movement of the occupants such as walking, running, jumping, or dancing. Vibration serviceability is based on the level of comfort that people have with the vibrations of a structure. Current design guidance uses the natural frequency of the structure to assess vibration serviceability. However, a phenomenon known as human-structure interaction suggests that there is a dynamic interaction between the structure and passive occupants, altering the natural frequency of the system. …