Effective tension

First, it is shown that liquids can flow cavitation-free through pressure regions that are significantly less than saturation vapor pressure corresponding to free-stream liquid temperature. For this condition, the liquid is locally in a thermodynamically metastable state of superheat, and as such, the flowing liquid can be expected to sustain these unusually low pressures only for relatively short periods of time. The maximum decrement of local pressure relative to stream vapor pressure that existed at, or just prior to, incipient cavitation is called, for engineering purposes herein, eflfective liquid tension. Effective tension may be viewed as a pressure difference tending to rupture, or cavitate, the liquid. 

Effective liquid tension, defined as the minimum pressure h min minus stream vapor pressure hvy in feet of liquid, is shown in Fig. 7 plotted as a function of free-stream velocity. The data show that appreciable effective tensions were always obtained in both liquid nitrogen and water, where the values obtained in nitrogen were about twice those in water for a given stream velocity. Values of effective tension increase with increasing stream velocity, apparently because the time that the liquids are exposed to low pressure decreases as stream velocity increases. The water data were obtained with demineralized, tap, and distilled water... 

Although liquid temperatures are uniform throughout the Venturi in noncavitating flow, the effective tensions obtained at incipient cavitation (Fig. 7) indicate that the fluid is locally superheated and thus not in a state of thermodynamic equilibrium. When the fluid ruptures or cavitates, a phase change occurs because the voids rapidly fill with vapor. Vapor generation requires heat of vaporization, which must be drawn from the surrounding liquid. This should result in a cooling of the vapor-liquid interface and a reduction in temperature around and within the cavity. If conditions within the cavity are in thermodynamic equilibrium, then a definite pressure drop should accompany the drop in temperature. 

A number of muscles cross over more than one joint. The length of these muscles maybe inadequate to permit complete ROM of all joints involved. When a multijoint muscle simultaneously shortens at all joints it crosses, further effective tension development is prevented. This phenomena is called active insufficiency. For example, when the hamstrings are tested as knee flexors with the hip extended, less tension can be developed than when the hamstrings are tested with the hip flexed. Therefore, when testing the strength of multijoint muscles, the position of aU involved joints must be considered. 

After the above strength check on the temporary and permanent wall face is performed, the effective tension limit of the soil nail at each stage can be finalized. For stability analysis, these effective tension values shall be used as the upper bound of the soil nail force that is considered in the stability analysis. 

When a trafhc harrier is installed on the top of the MSB wall, the truck impact (crash) loading on the top of the harrier needs to he considered. For an MSB wall, the designer can install a crash slab underneath the barrier such that the vertical wheel load on the crash slab resists the lateral crash loading. If the crash slab needs to be anchored down to resist overturning effects, tension piles can be installed within the reinforced soil body. 

First, during isometric tetanus, an early development of an approximately maximal pressure-head tension of Po = lkgwt/cm2, is followed by an ongoing slower expansion of the cross-section area, from Ao to Ae. This expansion process entails a proportional increase of the hydraulic force up to Fe = Po-Ae. Usually, the effective tension, Teff = Fe/Ao = Po-Ae/Ao, is reported. Thus, the Teff value... 

It appears that, from the equality of lie and monolayer coUapse occurs when the effective tension of the particle-covered interface is equal to zero (for which fl = % ). 

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