Cement grouting is an operation often carried out to consolidate and seal the rock mass in dam sites and tunnels. The quality and efficiency of a grouting operation depends on various factors such as water take, grout properties and grouting pressure. One of the parameters which have the highest effect is pressure since the application of excessive pressure causes the hydraulic fracture phenome...

in this study, mass transfer coefficients (mtc’s) of natural gas components during hydrate formation are reported. this work is based on the assumption that the transport of gas molecules from gas phase to aqueous phase is dominant among other resistances. several experiments were conducted on a mixture of natural gas at different pressures and temperatures and the consumed gas was monitored an...

a comprehensive mathematical model based on the discrete particle model and computational fluid dynamics was utilized to investigate mixing and segregation of particles in fluidized beds at high pressure. to quantify the extent of mixing in the bed, the lacey mixing index was used. simulations were carried out with different mass fractions of small particles at various pressures ranging from 1 ...

extended abstractintroductionsiberian high-pressure is one of the most important systems in climatology, which has been focused by all climatologists because of its influence area and expansion zone.unique features of this system including the expansion zone,the intensity of central pressure,which sometimes amounts to more than1075hp pressure at its core,its temperature and moisture characteris...

In this study, mass transfer coefficients (MTC’s) of natural gas components during hydrate formation are reported. This work is based on the assumption that the transport of gas molecules from gas phase to aqueous phase is dominant among other resistances. Several experiments were conducted on a mixture of natural gas at different pressures and temperatures and the consumed gas was monitored an...

The 70 ev positive and negative ion mass spectra of ring-substituted nitrobenzenes were studied. The influence of the substituent group on the fragmentation modes of the molecular ions is discussed. The effect of pressure in the formation of negative ions was also studied. As expected, the ratio of fragment ions to negative molecular ions decreased with increasing pressure in ion source.

Wall displacements and ground pressure acting on the lining of a tunnel increase with time. These time-dependent deformations are both due to face advance effect and to the time-dependent behavior of the rock mass.  Viscoelastic materials exhibit both viscous and elastic behaviors. Thorough this study, the effect of different linear viscoelastic models including Maxwell, Kelvin and Kelvin-Voigt...