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Full-Text Articles in Civil and Environmental Engineering
Legacy Effects In Material Flux: Structural Catchment Changes Predate Long-Term Studies, Daniel J. Bain, Mark B. Green, John L. Campbell, John F. Chamblee, Sayo Chaoka, Jennifer M. Fraterrigo, Sujay S. Kaushal, Sherry L. Martin, Thomas E. Jordan, Anthony J. Parolari, William V. Sobczak, Donald E. Weller, Wilfred M. Wollheim, Emery R. Boose, Jonathan M. Duncan, Gretchen M. Gettel, Brian R. Hall, Praveen Kumar, Jonathan R. Thompson, James M. Vose, Emily M. Elliott, David S. Leigh
Legacy Effects In Material Flux: Structural Catchment Changes Predate Long-Term Studies, Daniel J. Bain, Mark B. Green, John L. Campbell, John F. Chamblee, Sayo Chaoka, Jennifer M. Fraterrigo, Sujay S. Kaushal, Sherry L. Martin, Thomas E. Jordan, Anthony J. Parolari, William V. Sobczak, Donald E. Weller, Wilfred M. Wollheim, Emery R. Boose, Jonathan M. Duncan, Gretchen M. Gettel, Brian R. Hall, Praveen Kumar, Jonathan R. Thompson, James M. Vose, Emily M. Elliott, David S. Leigh
Civil and Environmental Engineering Faculty Research and Publications
Legacy effects of past land use and disturbance are increasingly recognized, yet consistent definitions of and criteria for defining them do not exist. To address this gap in biological- and ecosystem-assessment frameworks, we propose a general metric for evaluating potential legacy effects, which are computed by normalizing altered system function persistence with duration of disturbance. We also propose two distinct legacy-effect categories: signal effects from lags in transport and structural effects from physical landscape changes. Using flux records for water, sediment, nitrogen, and carbon from long-term study sites in the eastern United States from 1500 to 2000, we identify gaps …
Resonant Characteristics Of Rectangular Microcantilevers Vibrating Torsionally In Viscous Liquid Media, Tao Cai, Fabien Josse, Isabelle Dufour, Stephen M. Heinrich, Nicholas J. Nigro, Oliver Brand
Resonant Characteristics Of Rectangular Microcantilevers Vibrating Torsionally In Viscous Liquid Media, Tao Cai, Fabien Josse, Isabelle Dufour, Stephen M. Heinrich, Nicholas J. Nigro, Oliver Brand
Civil and Environmental Engineering Faculty Research and Publications
The resonant characteristics of rectangular microcantilevers vibrating in the torsional mode in viscous liquid media are investigated. The hydrodynamic load (torque per unit length) on the vibrating beam due to the liquid was first determined using a finite element model. An analytical expression of the hydrodynamic function in terms of the Reynolds number and aspect ratio, h/b (with thickness, h, and width, b) was then obtained by fitting the numerical results. This allowed for the resonance frequency and quality factor to be investigated as functions of both beam geometry and medium properties. Moreover, the effects of the aspect ratio on …
Fertilization Effects On The Ecohydrology Of A Southern California Annual Grassland, Anthony J. Parolari, Michael L. Goulden, Rafael L. Bras
Fertilization Effects On The Ecohydrology Of A Southern California Annual Grassland, Anthony J. Parolari, Michael L. Goulden, Rafael L. Bras
Civil and Environmental Engineering Faculty Research and Publications
Nitrogen limits leaf gas exchange, canopy development, and evapotranspiration in many ecosystems. In dryland ecosystems, it is unclear whether increased anthropogenic nitrogen inputs alter the widely recognized dominance of water and energy constraints on ecohydrology. We use observations from a factorial irrigation and fertilization experiment in a nitrogen-limited southern California annual grassland to explore this hypothesis. Our analysis shows growing season soil moisture and canopy-scale water vapor conductance are equivalent in control and fertilized plots. This consistency arises as fertilization-induced increases in leaf area index (LAI) are offset by reduced leaf area-based stomatal conductance, gs. We interpret this as evidence …
Measuring Bridge Construction Efficiency Using The Wireless Real-Time Video Monitoring System, Yong Bai, Jun Huan, Seonghoon Kim
Measuring Bridge Construction Efficiency Using The Wireless Real-Time Video Monitoring System, Yong Bai, Jun Huan, Seonghoon Kim
Civil and Environmental Engineering Faculty Research and Publications
To enhance the efficiency of bridge construction, the wireless real-time video monitoring system (WRITE) was developed. Utilizing the advanced technologies of computer vision and artificial neural networks, the developed system first wirelessly acquired a sequence of images of work-face operations. Then human pose analyzing algorithms processed these images in real time to generate human poses associated with construction workers who performed the operations. Next, a portion of the human poses were manually classified into three categories as effective work, contributory work, and ineffective work and were used to train the built-in artificial neural networks (ANN). Finally, the trained neural networks …
The Effect Of Thermal Hydrolysis Pretreatment On The Anaerobic Degradation Of Nonylphenol And Short-Chain Nonylphenol Ethoxylates In Digested Biosolids, Patrick J. Mcnamara, C. A. Wilson, M. T. Wogen, S. N. Murthy, J. T. Novak, Paige J. Novak
The Effect Of Thermal Hydrolysis Pretreatment On The Anaerobic Degradation Of Nonylphenol And Short-Chain Nonylphenol Ethoxylates In Digested Biosolids, Patrick J. Mcnamara, C. A. Wilson, M. T. Wogen, S. N. Murthy, J. T. Novak, Paige J. Novak
Civil and Environmental Engineering Faculty Research and Publications
The presence of micropollutants can be a concern for land application of biosolids. Of particular interest are nonylphenol diethoxylate (NP2EO), nonylphenol monoethoxylate (NP1EO), and nonylphenol (NP), collectively referred to as NPE, which accumulate in anaerobically digested biosolids and are subject to regulation based on the environmental risks associated with them. Because biosolids are a valuable nutrient resource, it is essential that we understand how various treatment processes impact the fate of NPE in biosolids. Thermal hydrolysis (TH) coupled with mesophilic anaerobic digestion (MAD) is an advanced digestion process that destroys pathogens in biosolids and increases methane …
Characteristics Of Laterally Vibrating Resonant Microcantilevers In Viscous Liquid Media, Russell Cox, Fabien Josse, Stephen M. Heinrich, Oliver Brand, Isabelle Dufour
Characteristics Of Laterally Vibrating Resonant Microcantilevers In Viscous Liquid Media, Russell Cox, Fabien Josse, Stephen M. Heinrich, Oliver Brand, Isabelle Dufour
Civil and Environmental Engineering Faculty Research and Publications
The characteristics of microcantilevers vibrating laterally in viscous liquid media are investigated and compared to those of similar microcantilevers vibrating in the out-of-plane direction. The hydrodynamic loading on the vibrating beam is first determined using a numerical model. A semi-analytical expression for the hydrodynamic forces in terms of the Reynolds number and the aspect ratio (beam thickness over beam width) is obtained by introducing a correction factor to Stokes’ solution for a vibrating plate of infinite area to account for the effects of the thickness. The results enable the effects of fluid damping and effective fluid mass on the resonant …