The xylem hydraulic efficiency and safety is usually measured on mechanically unstressed samples, although trees may be exposed to combined hydraulic and mechanical stress in the field. We analysed changes in hydraulic conductivity and vulnerability to drought-induced embolism during static bending of Picea abies and Pinus sylvestris branches as well as the effect of dynamic bending on the vuln...

According to the present situations that the construction amount of the gas drainage boreholes in mining seam is large and the gas drainage effect in low permeability coal seams doesn’t yield perfect, the hydraulic reaming technology in mining seam is proposed to increase the gas drainage efficiency. Through the gas flow method, the effective influence radius of hydraulic reaming is determined....

able information on relationships between size—expressed in terms of diameter and dry biomass—and hydraulic efficiency of woody structures at different scales, from stem segments to whole trees. Three data sets were constructed: the first described the relationship between segment diameter and hydraulic conductivity (kh; kg m s –1 MPa) in four species; the second, for the same four species, des...

Although climate change will alter both soil water availability and evaporative demand, our understanding of how future climate conditions will alter tree hydraulic architecture is limited. Here, we demonstrate that growth at elevated temperatures (ambient +5 °C) affects hydraulic traits in seedlings of the deciduous boreal tree species Populus tremuloides, with the strength of the effect varyi...

The increasing demand for sufficient and clean energy forces industrial and service companies to align their strategies towards efficient consumption. This trend refers also to the residential building sector. There, large amounts of energy consumption are caused by house and facility heating. Many of the operated hot water heating systems lack hydraulic balanced working conditions for heat dis...

Oil shale is a kind of potential alternative energy source for petroleum and has attracted the attention of energy researchers all over the world. Borehole hydraulic mining has more prominent advantages than both conventional open-pit mining and underground mining. It is very important to attempt to use the borehole hydraulic mining method to exploit underground oil shale. The nozzle is the key...

Xylem within trees varies in its hydraulic efficiency and safety. Trees at the alpine timberline were expected to exhibit a hydraulic architecture protecting the leader shoot from winter embolism. Hydraulic and related anatomical parameters were compared as well as seasonal courses of winter embolism in leader shoots and twigs of Norway spruce trees growing at 2000 m. Leader shoots had a 1.4-fo...

Hydropower plays a key role in the actual energy market due to its fast response and regulation capacity. In that way, hydraulic turbines are increasingly demanded to work at off-design conditions, where complex flow patterns and cavitation appear, especially in Francis turbines. The draft tube cavitation surge is a hydraulic phenomenon that appears in Francis turbines below and above its Best ...

This study presents application of Dynamic Programming towards finding globally optimal control policies of a new, highly-efficient hydraulic elevator architecture. The architecture employs an actuator, three accumulators, and two hydraulic circuits bridged by a hydraulic transformer. An auxiliary electric motor exists only to compensate for system losses. Prior research identified a multitude ...