Particle flow numerical simulation was used to reproduce the transient unloading process of a deep-buried single fracture tunnel. The influence characteristics on effect analyzed from aspects stress state, deformation characteristics, propagation, and energy conversion. results shows that surrounding rock field tunnel is divided into four areas: weak area I, strong II, adjustment III, initial I...

6 Valveless, tubular pumps are widespread in the animal kingdom, but the mechanism by which these pumps generate fluid flow are often in dispute. Where the pumping mechanism of many organs was once described as peristalsis, other mechanisms, such as dynamic suction pumping, have been suggested as possible alternative mechanisms. Peristalsis is often evaluated using criteria established in a tec...

Numerical simulations of pulsatile blood flow through a symmetrical branch modeling the aortic bifurcation were carried out to assess several hemodynamic theories of atherogenesis by comparing the distribution of hemodynamic variables with that of early lesions in arterial branches. Considerable spatial and temporal variations in wall shear were found when the flow was pulsatile; the highest va...

Vacuum, b-phase duration, and liner compression are 3 milking machine factors that affect peak milk flow rate; however, extreme values of these factors can also have negative effects on teat tissue health. The main and interactive effects of vacuum, b-phase duration, and liner compression on peak milk flow rate were studied by independently controlling these causal variables over a wide range o...

OBJECTIVE To use an electronic model of human circulation to compare the hemodynamic effects of different durations of chest compression during external CPR, both with and without interposed abdominal compression (IAC). METHODS An electrical analog model of human circulation was studied on digital computer workstations using SPICE, a general-purpose circuit simulation program. In the model th...

The mechanism of forward flow produced by precordial compression during CPR was investigated with the aid of echocardiographic and hemodynamic measurements in anesthetized, mechanically ventilated domestic pigs. Both mitral and tricuspid valves opened during compression diastole and closed during compression systole. Valve motion persisted throughout resuscitation in 17 of 22 animals which were...

Increasing automation of business processes and industrial demand for complex workflow features have led to the development of more flexible and agile workflow concepts. One of those concepts is the use of goal-oriented workflows, which rely on ideas derived from agent technology like describing the workflows based on a goal hierarchy. While this reduces the gap between business view and IT vie...

to enhance the understanding of the impact of obstacle buildings on pollution transportationand dispersion in the atmospheric boundary layer, it is necessary to know the atmospheric flow characteristics over terrains. wind flow characteristics in a boundary layer over a step-shaped cliff topography model with rough and smooth surfaces were studied numerically using computational fluid dynamics ...

The focus of this paper is to study the flow crossover between two adjacent flow channels in a proton exchange membrane (PEM) fuel cell with serpentine flow field design in bipolar plates. The effect of gas diffusion layer (GDL) deformation on the flow crossover due to the compression in a fuel cell assembly process is particularly investigated. A three-dimensional structural mechanics model is...