This paper presents the application of hydraulic fracturing method in Romania, exemplified by three case studies. In current conditions which oil and gas prices have risen above limit affordability, one few producers Europe, is trying to solve problems that arisen through various methods, are as follows: offshore drilling, underground storage, field rehabilitation increasing efficiency applied ...

In this paper, the hydraulic and heat-transfer properties of two sets of artificially fractured granite samples are investigated. First, the morphological information is determined using 3D modelling technology. The area ratio is used to describe the roughness of the fracture surface. Second, the hydraulic properties of fractured granite are tested by exposing samples to different confining pre...

Hydraulic cylinder actuators are used extensively in industrial, construction and agricultural works. The small sized outlet ports of the cylinders resist the flow of discharged oil; and as a result the piston motion is slowed down. This causes a lot of heat generation and energy loss within the actuators. The study investigates and analyzes the possibilities of reducing the hydraulic resistanc...

background: one of the first‑line assessment tools for fetal surveillance is nonstress test (nst), although it is limited by a high rate of false‑nonreactive results. this study was performed to investigate if external stimulation from vibroacoustic and halogen light could help in provoking fetal responsiveness and altering nst results. materials and methods: this is a clinical trial. sampling ...

The concept of a hydraulic axis plays a central role within the design and analysis of hydraulic systems. A hydraulic axis comprises working, control, and supply elements that realize a subfunction of a hydraulic system. Analyzing a system’s functional structure means to identify the hydraulic axes along with their couplings. The paper in hand addresses this problem; it presents concepts and al...

1 Abstract The paper presents a hydraulic astable multivibrator system. The system consists of hydraulic resistors, hydraulic capacitors and hydraulic pressure controlled valves. The system is designed, realised and tested. The measured system behaviour agrees well with the model simulations. The free running frequency of the multivibrator is 0.18 Hz and the output pressure swing is 90% of the ...

Hydraulic excavator energy saving is important to relieve source shortage and protect environment. This paper mainly discusses the energy saving for the hybrid hydraulic excavator. By analyzing the excess energy of three hydraulic cylinders in the conventional hydraulic excavator, a new boom potential energy recovery system is proposed. The mathematical models of the main components including b...

We analyze the motion of viscous and incompressible liquids in the annular space of controllable hydraulic resistances with a cylindrical linear slide-valve. This theoretical study focuses on the turbulent and steady-state motion regimes. The hydraulic resistances mentioned above are the most frequent type of hydraulic resistances used in hydraulic actuators and automation systems. To study the...