Filling process efficiency

The microbiological contamination of products (bioburden) is minimal prior to sterilization. There is a working limit on contamination immediately before sterilization that is related to the efficiency of the method to be used and the risk of pyrogens. All solutions, in particular large-volume parenterals, are passed through a bacteria retentive filter, if possible immediately before the filling process. Where aqueous solutions are held in sealed vessels, any pressure-release outlets are protected, e.g., by hydrophobic microbial air filters. 

Let us consider one more physical phenomenon, which can influence upon PT sensitivity and efficiency. There is a process of liquid s penetration inside a capillary, physical nature of that is not obvious up to present time. Let us consider one-side-closed conical capillary immersed in a liquid. If a liquid wets capillary wall, it flows towards cannel s top due to capillary pressure pc. This process is very fast and capillary imbibition stage is going on until the liquid fills the channel up to the depth l , which corresponds the equality pcm = (Pc + Pa), where pa - atmospheric pressure and pcm - the pressure of compressed air blocked in the channel. 

Phillips Petroleum Company developed an efficient slurry process used for the production of both HDPE and LLDPE (Eig. 6). The reactor is built as a large folder loop containing long mns of pipe from 0.5 to 1 m ia diameter coimected by short horizontal stretches of pipe. The reactor is filled with a light solvent (usually isobutane) which circulates through the loop at high speed. A mixed stream containing ethylene and comonomers (1-butene,... 

The Cardiac Cycle. The heart (Eig. lb) performs its function as a pump as a result of a rhythmical spread of a wave of excitation (depolarization) that excites the atrial and ventricular muscle masses to contract sequentially. Maximum pump efficiency occurs when the atrial or ventricular muscle masses contract synchronously (see Eig. 1). The wave of excitation begins with the generation of electrical impulses within the SA node and spreads through the atria. The SA node is referred to as the pacemaker of the heart and exhibits automaticity, ie, it depolarizes and repolarizes spontaneously. The wave then excites sequentially the AV node the bundle of His, ie, the penetrating portion of the AV node the bundle branches, ie, the branching portions of the AV node the terminal Purkinje fibers and finally the ventricular myocardium. After the wave of excitation depolarizes these various stmetures of the heart, repolarization occurs so that each of the stmetures is ready for the next wave of excitation. Until repolarization occurs the stmetures are said to be refractory to excitation. During repolarization of the atria and ventricles, the muscles relax, allowing the chambers of the heart to fill with blood that is to be expelled with the next wave of excitation and resultant contraction. This process repeats itself 60—100 times or beats per minute... 

Metal Cleaning. Citric acid, partially neutralized to - pH 3.5 with ammonia or triethanolamine, is used to clean metal oxides from the water side of steam boilers and nuclear reactors with a two-step single fill operation (104—122). The resulting surface is clean and passivated. This process has a low corrosion rate and is used for both pre-operational mill scale removal and operational cleaning to restore heat-transfer efficiency. 

One such process is the TAP process, the basic patent being held by Dow. It was developed in Japan by Asahi in conjuction with Toshiba. Foam expansion after mould filling is made possible by use of retractable mould cores. Because of the difficulty of allowing expansion in more than one direction this process has been largely limited to the production of flat products. Efficient gas sealing systems are also vital and the process needs close control. For this reason it has not been widely used in either Europe or North America. 

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