conclusions parametric models may provide complementary data for clinicians and researchers about how risks vary over time. the weibull model seemed to show the best fit among the parametric models of the survival of hemodialysis patients. results the results of a multivariate analysis of the variables in the parametric models showed that the mean serum albumin and the clinic attended were the ...

The Graphene based single electron transistor (SET) as a coulomb blockade device need to be explored .It is a unique device for high-speed operation in a nano scale regime. A single electron transfers via the coulomb barriers, but its movement may be prevented by coulomb blockade, so its effect is investigated in this research. The conditions of coulomb blockade and its controlling factors such...

Abstract Given the complexities of reservoir exploration and development, it is vital to understand geomechanical properties well in drilling operation. In constructing a mechanical model earth, combination environmental parameters, as magnitude direction stresses, used. this study, stress analysis its effect on azimuth deviated an oil field located southwestern Iran are investigated. Necessary...

Abstract Wellbore instability problems cause nonproductive time, especially during drilling operations in the shale formations. These include stuck pipe, caving, lost circulation, and tight hole, requiring more time to treat therefore additional costs. The extensive hole collapse problem is considered one of main challenges experienced when Zubair formation. In turn, it caused by increasing wel...

The load displacement relationship of shallow rigid strip anchors embedded in sands and subjected to uplift pressures has been examined by using the finite element method. The soil medium is modeled as a linear elastic-perfect plastic material following Mohr-Coulomb failure criterion and an associated flow rule. The computed load displacement response is presented in non-dimensional form. The u...

This paper proposes a new interface constitutive model for fully grouted rock-bolts and cable-bolts based on pull-out test results. A database was created combining published experimental data with in-house tests. By means of comprehensive framework, Coulomb-type failure criterion accounting friction mobilization defined. During the elastic phase, in which joint is not yet created, proposed pro...

In order to research on stress distribution and failure depth of mining floor during the first weighting of main roof, based on the analysis of abutment pressure distribution in this case, an elastic mechanics model is established to calculate the stress of any point in the floor, expressions for this model are deduced, and meanwhile a failure criterion of floor rock is put forward according to...

Structural changes during sludge treatments impact flowability and raise severe technical issues. In this study, the consistency is analysed using thread rolling test. Transition from pasty to granular-like material occurs at a total solid (TS) content of 43 wt%. A granular rheometer used characterize sludge's over wide range TS content. The typical powder-like behaviour recorded whatever conte...

The effective phase change from fluid behaviour to solid behaviour, that too often occurs in granular flow and brings with it such unwelcome events as funnel flows in hoppers and clogging of other material handling devices, is studied using a discrete particle computer simulation of a Couette flow with gravity. This simulation exhibits the full range of granular flow behaviour, from a stagnant ...