A Transition region

Dynamic Measurements. Dynamic methods are requited for investigating the response of a material to rapid processes, studying fluids, or examining a soHd as it passes through a transition region. Such techniques impart cycHc motion to a specimen and measure the resultant response. 

A transition region that extends to about 8 nozzle diameters. 

Ripple flow has an upward-moving wavy layer of liquid on the pipe wall it may be thought of as a transition region to annular, annular mist, or film flow, in which gas flows in the core of the pipe while an anniilus of hquid flows up the pipe wall. Some of the liquid is entrained as droplets in the gas core. Mist flow occurs when all the liquid is carried as fine drops in the gas phase this pattern occurs at high gas velocities, typically 20 to 30 m/s (66 to 98 ft/s). 

Next, the straight-sided tension specimen has a transition region that is created by thickness change (instead of the width change of the ASTM D 638 specimen) as shown in Figure 2-22. Failures typically occur either in the bonded tabs or in the gage section. If the bonded tabs fail, then the failure load is never a measure of the subject material s strength ... 

A photovoltaic cell (often called a solar cell) consists of layers of semiconductor materials with different electronic properties. In most of today s solar cells the semiconductor is silicon, an abundant element in the earth s crust. By doping (i.e., chemically introducing impurity elements) most of the silicon with boron to give it a positive or p-type electrical character, and doping a thin layer on the front of the cell with phosphorus to give it a negative or n-type character, a transition region between the two types... 

This is the basis for establishing the condition or type of fluid flow in a pipe. Reynolds numbers below 2000 to 2100 are usually considered to define laminar or thscous flow numbers from 2000 to 3000-4000 to define a transition region of peculiar flow, and numbers above 4000 to define a state of turbulent flow. Reference to Figure 2-3 and Figure 2-11 will identify these regions, and the friction factors associated with them [2]. 

Note that the break at Point A on Figure 10-67B at Re = 2,100 indicates where the film is believed to become turbulent. McAdams discusses the two regions on the figure, streamlined at the top and turbulent on the way down, with a transition region in between ... 

V3 to V4. A transition region of no present importance in analytical chemistry. 

Between the laminar and turbulent zones, there exists a transition region in which the viscous arid inertial forces are of comparable magnitudes. No simple mathematical relationship exists between Np and Re in this flow region and, at a given value of Re, N p must be obtained from the appropriate power curve. 

This is a transitional region in which reaction kinetics and mass transfer resistance both affect the overall reaction rate. 

Careful study of various fluids in tubes of different sizes has indicated that laminar flow in a tube persists up to a point where the value of the Reynolds number (NRt = DVp/n) is about 2000, and turbulent flow occurs when NRe is greater than about 4000, with a transition region in between. Actually, unstable flow (turbulence) occurs when disturbances to the flow are amplified, whereas laminar flow occurs when these disturbances are damped out. Because turbulent flow cannot occur unless there are disturbances, studies have been conducted on systems in which extreme care has been taken to eliminate any disturbances due to irregularities in the boundary surfaces, sudden changes in direction, vibrations, etc. Under these conditions, it has been possible to sustain laminar flow in a tube to a Reynolds number of the order of 100,000 or more. However, under all but the most unusual conditions there are sufficient natural disturbances in all practical systems that turbulence begins in a pipe at a Reynolds number of about 2000. 

Figure 2.9 Mott-Littleton method of dividing a crystal matrix for the purpose of calculating defect energies. Region I contains the defect and surrounding atoms, which are treated explicitly. Region lib is treated as a continuum reaching to infinity. Region Ha is a transition region interposed between regions I and lib.

This comparison suggests that there will be a transition region between materially-dominated and magnetically-dominated flow. The region inside of which the stellar magnetic field controls the flow is called the magnetosphere. To within a factor of 2-3, the radius at which the transition occurs is (e.g., Ghosh Lamb 1979)... 

The continuity of the linewidth over a large temperature range, above room temperature, that has previously been reported (IJ) and is further detailed here does not reveal any change in the vicinity of the a transition region (80-100°C). Major changes are found in broad line proton NMR experiments, which measure linewidths or second moments. ( ) There is, however, no discrepancy between these results since the a transition is a property of the crystalline regions. The proton measurements... 

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