Pumps effect

Pumping effectiveness or pumping per power is important for flow controlled processes [29]. 

Oldshue [29] expresses pumping effectiveness as pumping per power and recognizes it as a key function for processes that are flow controlled or need more flow- than head or shear. 

This is a condition which occurs when the feedwater pump is unable to deliver feedwater to the boiler although the feed tank has water available. The temperature of the feed-water coupled with the possible suction effect from the feedwater pump in the line between the feed tank and the pump effectively drops the pressure, causing the feed-water to flash to steam. The pump then loses its water supply. 

Triplett KA, Chiaasiaah SM, Abdel-Khahk SI, Sadowski JL (1999a) Gas-liquid two-phase flow in micro-channels. Part 1 two-phase flow patterns. Int J Multiphase How 25 377-394 Yuan H, Prosperetti A (1999) The pumping effect of growing and codapsing bubbles in a tube. Micromech Microeng 9 402-413... 

When the pump is turned off, the condensation nuclei count decreases by ventilation and plate-out to that observed before the sampling process. Thus, there must be a process during the sampling period that shifts the particle size to a size detectable by the CNC. The "pump effect" has further been found to be proportional to the S(>2 concentrations (Figure 6). It was not observed when... 

Figure 6. Proportionality between the "pump effect" and the concentrations of...

The plasma membrane Ca2+-ATPase pump effects outward transport of Ca2+ against a large electrochemical gradient for Ca2+. The mechanism of the pump involves its phosphorylation by ATP and the formation of a high-energy intermediate. This basic mechanism is similar for both the plasma membrane and ER pumps however, the structures of these distinct gene products are substantially different. As discussed below, the ER pump, sometimes called a sarcoendoplasmic reticulum Ca2+-ATPase (SERCA) pump, is inhibited potently by certain natural and synthetic toxins that do not affect the plasma membrane pump. The plasma membrane pump, but not the SERCA pump, is controlled in part by Ca2+ calmodulin, allowing for rapid activation when cytoplasmic Ca2+ rises. 

In-well aeration is the process of injecting air into the lower portion of a dual-screened well with perforations at the bottom and above the water table. As the bubbles rise, they expand, which causes the mixed mass of air and water to have less density. The result is an air-lift pump effect. When the water rises and exits the upper perforations, replacement water enters the bottom of the well. The result is a circulation cycle. Free air does not enter the aquifer, but dissolved air (and oxygen) travels with the circulating water. Figure 9.4 is a schematic diagram of in-well aeration. 

An absorption refrigerator or heat pump is economically attractive because it uses inexpensive heat input rather than the expensive electrical work input to produce the refrigeration or heat pump effect. 

Pumps where the pumping effect is based mainly on the diffusion of gases into a gas-free high speed vapor jet (vapor pumps)... 

Pv2 Ps Pp2 relatively large gas ballast pump is required. Since the quantity of air involved during a pumping process that uses condensers is not necessarily constant but alternates within more or less wide limits, the considerations to be made are more difficult. Therefore, it is necessary that the pumping speed of the gas ballast pump effective at the condenser can be regulated within certain limits. 

At the end of the Fifties, it became possible - through a turbine-like design and by modification of the ideas of Gaede - to produce a technically viable pump the socalled Turbomolecular pump . The spaces between the stator and the rotor disks were made in the order of millimeters, so that essentially larger tolerances could be obtained. Thereby, greater security in operation vras achieved. However, a pumping effect of any significance is only attained when the circumferential velocity (at the outside rim) of the... 

This effect has been utilized for a long time in condensers (see 2.1.5) mainly in connection with chemical processes previously the baffle on diffusion pumps used to be cooled with refrigerating machines. Also in a sealed space (vacuum chamber) the formation of condensate on a cold surface means that a large number of gas molecules are removed from the volume they remain located on the cold surface and do not take part any longer in the hectic gas atmosphere within the vacuum chamber. We then say that the particles have been pumped and talk of cryopumps when the pumping effect is attained by means of cold surfaces. 

Low-temperature distillate fuel pumpability and viscosity can be reduced below that of an untreated fuel. Below the cloud point, fuel which does not contain a wax crystal modifier is difficult to handle and pump effectively. Wax crystal modifiers help minimize pumpability problems related to yield stress and viscosity. 

Mixers share a common functionality with pumps. The power imparted by the mixer, via the impeller, to the system is akin to a pumping effect and is characterized in terms of the shear and flow produced as... 

Another example for the HMRRD electrode is given in Fig. 9 for Fe in alkaline solutions [12, 27]. The square wave modulation of the rotation frequency co causes the simultaneous oscillation of the analytical ring currents. They are caused by species of the bulk solution. Additional spikes refer to corrosion products dissolved at the Fe disc. This is a consequence of the change of the Nemst diffusion layer due to the changes of co. This pumping effect leads to transient analytical ring currents. Besides qualitative information, also quantitative information on soluble corrosion products may be obtained. The size of the spikes is proportional to the dissolution rate at the disc, as has been shown by a close relation of experimental results and calculations [28-30]. As seen in Fig. 7, soluble Fe(II) species are formed in the po-... 

The pitch direction, i. e., the direction of the angle of rotation of the thread. If the thread of the element runs counter to the direction of rotation of the screw shafts, one obtains a conveying element. If the thread runs synchronously with the screw shaft rotation direction, the screw element will have a backward-pumping effect (Fig. 12.4). 

Myocardial hypertrophy The heart increases in size, and the chambers dilate. Initially, stretching of the heart muscle leads to a stronger contraction of the heart. However, excessive elongation of the fibers results in weaker contractions. This type of failure is termed systolic failure and is a result of a ventricle unable to pump effectively. Less commonly, patients with CHF may have diastolic dysfunction—a term applied when the ventricles ability to relax and accept blood is impaired by structural changes, such as hypertrophy. The thickening of the ventricular wall and subsequent decrease in ventricular volume decreases the ability of heart muscle to relax. In this case, the ventricle does not fill adequately, and the inadequacy of cardiac output is termed diastolic heart failure. 

---