Hydrostatic method

To generate a lubricating film within a bearing, the opposed surfaces must be forced apart by pressure generated within the fluid film. One way is to introduce the fluid under sufficient pressure at the point of maximum loading, but this hydrostatic method, although equally effective at all speeds, needs considerable power and is consequently to be avoided whenever a satisfactory alternative exists. 

For the solid-state extrusion several tedmiques have been developed. They are either bz ed on pure ram extrusion or on hydrostatic methods. 

J. Zeleny, The electrical discharge from liquid points, and a hydrostatic method of measuring the electric intensity at their surfaces, Phys. Rev., 10 (1917) 1. 

Zeleny, J. The Electrical Discharge from Liquid Points, and A Hydrostatic Method of Measuring the Electric Intensity at Their Surfaces, Phys. Rev. 3, 69-91 (1914). 

High-pressure NMR experiments have been performed for more than 40 years using techniques ranging from hydrostatic methods employing hydraulic presses and titanium alloy vessels to the use of glass and sapphire tubes. In this article we will focus on sapphire tubes because they represent the only high-pressure NMR tool we are utilising. 

Europe. The procedure is usually performed with saline solution (Fig. 1.55). Studies have shown a high reduction rate (76%-95%) with few complications, results similar to those of other hydrostatic methods (Wang and Liu 1988 Woo et al. 1992 Riebel et al. 1993 Rohrschneider and TrSger 1995). The principal advantage of this technique is the lack of radiation exposure. As a result, there is no limit to the procedure time, a fact that may improve the success rate. US has a high accuracy and reliability for monitoring the reduction process and for the visualization of all components of the intussusception. 

The hold-up of the dispersed phase was determined by several techniques as there is no particular method which is reliable in all cases. In spray columns the hydrostatic method gives good results but this was not applicable in agitated columns. A comparison of different possible methods and their applicability is given in Table 2. 

Figure 3 Example of spray column with measuring points MS 1 to 6 Separate sampling of both phases for determination of concentration profiles, ES-OS ports for hold-up measurement by hydrostatic method, tracer injection, FA,FB windows for photographic determination of drop size.

Zeleny, J., The electrical discharge from Liquid Points, and a Hydrostatic Method of measuring the electric intensity at their surface. Physical Review, 1914, 3(2), 69-91. 

A great variety of level measurement techniques are available. These involve point-contact, visual, buoyancy, float, and hydrostatic methods, and radio-frequency, ultrasonic, microwave, nuclear radiation, resistance tape, and thermal level systems [3]. 

In the hydrostatic method, the pressure at the base of the liquid, which is related to the height of the liquid above the base, is measured. The measured pressure depends directly on the liquid height according to the Bernoulli equation or mechanical energy balance [10-12] [Eq. (6), where Z2 is the level at the surface of the liquid, Zi is the level at the base, p2 is the pressure at the surface, pi is the pressure at the base, p is the liquid density, and g is the acceleration due to gravity). In pressurized reservoirs one measures the pressure difference p — P2 between the base and the gas space. 

The determination of porosity by the hydrostatic method comprises a determination of the weight and saturation of it by boiling in water or saturation in vacuum by another liquid that does not interact with the refractory (in the case of materials that can react with water) [16, 17]. Then the saturated sample is weighed in the liquid (water) and in air. If the tested sample may react with water, the determination of apparent, real, and open porosities is performed in vacuum and then absorbed by kerosene, xylol, and ethyl or butyl alcohol according to ASTM C830-00 [18]. The application of melted paraffin or wax for the determination of the apparent, real, and open porosities is made according to ASTM C914-95 (1999) [19]. 

ISO 12985-2 2000. Carbonaceous materials used in the production of aluminium - baked anodes and cathode blocks - Part 2 determination of apparent density and of open porosity using a hydrostatic method. 

Table 11 shows the results of open porosity for the samples before and after aluminum electrolysis, which are tested by hydrostatic method. Obviously, all the sample porosity after aluminum electrolysis had been decreased, which was due to flie pores within the cathode samples filled with the molten electrolyte during aluminum electrolysis. Furfliermore, the carbon cathode sample without the function and gradient layers had file biggest increase in open porosity after electrolysis (about 18.26%), while TG2 sample with FGM layer was file lowest (about 6.34%). This means that the FGM cathode had the least penetrated electrolyte filled into the inner pores, which are in good agreement with SEM observation illustrated above. 

The density of samples was determined by the hydrostatic method using AR-240 balance (Ohaus, Switzerland) with accuracy 2x10 kg. 

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