نتایج جستجو برای: hydraulic failure

تعداد نتایج: 399750  

2014
Michalis Fragiadakis Savvas Xanthos Demetrios G. Eliades Anastasis Gagatsis Symeon Christodoulou

Presented herein is a methodology for the seismic and hydraulic assessment of the re-liability of urban water distribution networks (UWDN) based on general seismic assessment standards, as per the American Lifelines Alliance (ALA) guidelines, localized historical records of critical risk-of-failure metrics pertaining to the specific UWDN under assessment, and hydraulic simulations using adapted...

Operational failures in centrifuge pumps could be hydraulic or mechanical. However, most of these mechanical and hydraulic failures are connected cause of their operational nature and finding the right cause is due to considering numerous mechanical and hydraulic signs and parameters in pumps. On the other hand, due to non-linear and fluctuant behavior of pumps in the matter of time and not pre...

2010
Juliana S. Medeiros William T. Pockman

Juvenile woody desert perennials often exhibit higher rates of transpiration than co-occurring adults, which may facilitate establishment by increasing carbon gain when water is plentiful, but increase the risk of hydraulic failure during drought. We tested three hypotheses regarding the role of hydraulic limits in two size classes of Larrea tridentata: 1) small plants grow faster and use more ...

2018
David Valentin Alexandre Presas Matias Bossio Mònica Egusquiza Eduard Egusquiza Carme Valero

Nowadays, hydropower plays an essential role in the energy market. Due to their fast response and regulation capacity, hydraulic turbines operate at off-design conditions with a high number of starts and stops. In this situation, dynamic loads and stresses over the structure are high, registering some failures over time, especially in the runner. Therefore, it is important to know the dynamic r...

2018
Guillaume Charrier Sylvain Delzon Jean-Christophe Domec Li Zhang Chloe E L Delmas Isabelle Merlin Deborah Corso Andrew King Hernan Ojeda Nathalie Ollat Jorge A Prieto Thibaut Scholach Paul Skinner Cornelis van Leeuwen Gregory A Gambetta

Grapevines are crops of global economic importance that will face increasing drought stress because many varieties are described as highly sensitive to hydraulic failure as frequency and intensity of summer drought increase. We developed and used novel approaches to define water stress thresholds for preventing hydraulic failure, which were compared to the drought stress experienced over a deca...

2013
Chen Mian Wang Zheng Yuan Jianbo Liu Ming

A series of experiments were performed to determine rock mechanical parameters related to was studied. Experimental results show that the coal seam in the study areas has a relatively low elastic modulus, high Poisson’s ratio, high fragility and is easily broken and compressed. The coal seam is considered as a transversely isotropic medium, since the physical properties in the direction of bedd...

2012
H. Emamjomeh M. Hosseini

This paper presents a new weighted entropy-based measure for assessing reliability of water distribution networks. The proposed methodology considers both of mechanical uncertainties (probability of pipe failure) and uncertainties due to hydraulic parameters (flow in pipe) simultaneously. In this methodology a penalty function is defined for different links of the network based on their probabi...

2015
Yann Salmon José M. Torres‐Ruiz Rafael Poyatos Jordi Martinez‐Vilalta Patrick Meir Hervé Cochard Maurizio Mencuccini

Understanding physiological processes involved in drought-induced mortality is important for predicting the future of forests and for modelling the carbon and water cycles. Recent research has highlighted the variable risks of carbon starvation and hydraulic failure in drought-exposed trees. However, little is known about the specific responses of leaves and supporting twigs, despite their crit...

2015
Xiaohui Zhao Fuyong Li Yu Liu Yanjun Fan

Hydraulic support is the main supporting equipment of the coal mining systems, and they are usually subjected to fatigue failure under the high dynamic load. The fracture positions are generally at welded joints where there is a serious stress concentration. In order to investigate and further improve the fatigue strength of hydraulic support, the present work first located the possible positio...

Journal: :The New phytologist 2015
John S Sperry David M Love

Climate change exposes vegetation to unusual drought, causing declines in productivity and increased mortality. Drought responses are hard to anticipate because canopy transpiration and diffusive conductance (G) respond to drying soil and vapor pressure deficit (D) in complex ways. A growing database of hydraulic traits, combined with a parsimonious theory of tree water transport and its regula...

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