Primary pump

Install a small booster pump int(t the suction piping. The booster pump would have a reduced NPSHr for the system feeding it, and the discharge head of the booster pump would increase the Ha to the primary pump. 

The primary pumping capacity of an impeller is determined by the impeller diameter, the Pumping number, and the rotational speed. The Pumping number Nq is defined by [13]... 

The two primary pumps with AC and DC pony motors flow 18,000 gpm of heavy water through the core for cooling. Following 60 MW operation, for 3 minutes, forced flow is needed to remove the decay heat. Upon loss of pony motors and primary pumps, forced flow is established through the shutdown cooling water system consisting of two pumps in parallel - one pump running and the other on standby. 

The primary pump types for the chemical industry for horizontal and vertical inline applications have been standardized in ANSI B-123, ANSI Std B73.1M for horizontal end suction centrifugal pumps, and ANSI B73.2M for vertical inline centrifugal pumps. The standards are in a continuous process of upgrading to suit requirements of industry and the manufacturers. The API-610 standard is primarily a heavy duty application, such as is used for the refinery and chemical industry requirements. This is the only true world pump [21] standard, although the International Organization for Standardization (ISO) is studying such an improved design [20]. 

Small to medium size water-to-water heat pumps are considered in this system. Since the primary pumps are common to all the heat pumps, this system may not be ideal for projects where large size multiple heat pumps are used. It is better if dedicated primary pumps are used in the case of large multiple heat pumps. This is discussed in Section 6.4.1. 

CENTRAL MULTIPLE HEAT PUMP SYSTEM WITH PRIMARY PUMPING... 

Figure 23. Central multiple heat pump system with ground loop and primary pumping...

With metal gaskets and moderate bakeout, turbo pumps can reach pressure below 10-9 torr without traps. They can be started at a pressure up to 1 torr. The time required to reach full pumping speed ( lmin) is much shorter than for diffusion pumps. Also these pumps must be backed by a primary pump. 

Primary coolant hydraulic model (one primary pump). 

Boiteau, L., Rlasson, R., Collet, H., etal. (2002). Molecular origin of life when chemistry became cyclic. The primary pump, a model for prebiotic emergence and evolution of petides. In Fundamentals of Life, eds. G. Ralyi, C. Zucchi, and L. Caglioti. Elsevier, pp. 211-18. 

Moriyama, Y., and Futai, M. (1990). H(+)-ATPase, a primary pump for accumulation of neurotransmitters, is a major constituent of brain synaptic vesicles. Biockem. Biophys. Res. Commun. 173, 443-448. 

The term ion pump, synonymous with active ion-transport system, is used to refer to a protein that translocates ions across a membrane, uphill against an electrochemical potential gradient. The primary pumps do so by utilization of energy derived from various types of chemical reactions such as ATP hydrolysis, electron transfers (redox processes), and decarboxylations, or from the absorption of light (Table 1). Secondary pumps are symport and antiport systems that derive the energy for uphill movement of one species from a coupled downhill movement of another species. The electrochemical gradient driving the latter movement is often created by a primary pump. 

New types of primary pumps are currently being discovered, and the spectrum of ATP-driven pumps now covers transporters of small anions as well as more complex molecules, some of which have to be extruded from the cells because of their toxicity. In view of the wide scope of the topic, we have found it necessary to narrow the discussion to selected examples that illustrate the principles pertaining to the primary ion pumps and the methodology used for studying them. Hence, the present chapter deals most extensively with the Na+-K+- and Ca2+-ATPases of P-type, whose mechanisms and structures have been studied in great detail. 

Systems Based on Amino Acid and Peptides Only The Primary Pump Scenario... 

This Primary Pump scenario is a model of protometabolism [147]. Its features served to build a theoretical model (limited to dipeptides, Scheme 38) by which homo chirality could have emerged from a racemic amino acid world without needing autocatalysis [196]. Actually, this model shows that stereoselectivity at three different stages (with corresponding selectivity ratios in brackets) NCA coupling with AA (a), dipeptide hydrolysis (fi), and dipeptide epimerization (y) is enough to promote homochirality. The racemic composition is not stable for certain values of the set of selectivity ratios a, ft, y (taken as parameters) and provided the system is supplied with chemical energy to continuously recycle the amino acid into NCA. 

Fig. 5 The Primary Pump, a peptide-based protometabolism scenario [146] involving the following steps I amino acid N-carbamoylation II concentration through drying III NO -mediated CAA activation IV dissolution through watering (by e.g. sea water) V NCA reaction in aqueous phase (Va NCA hydrolysis Vb condensation with AA or peptide) VI slow hydrolysis of peptide bonds VII a-carbon epimerization (Vila of amino acid and CAA VNb of peptide residues). Additional steps corresponding to peptide N-carbamoylation/nitrosation have not been mentioned for the sake of clarity. It is worth mentioning that although the N-carbamoylation of peptides renders them unre-active towards NCA, this is reverted by NOx-mediated nitrosation [197], thus keeping peptides within the polymerization process...

Some typical disturbance patterns and control difficulties are summarized here. A detailed discussion is made in (1). Hydraulic disturbances are significant in amplitude. Diurnal variations as well as shock loads from rain storms or melting snow may cause major upsets. Significant disturbances also appear from internal sources like primary pumps, back-washing of deep bed filters or return sludge flow rate changes. The amplitudes are such, that quasi-stationary of linear control methods are seldom adequate. 

To reach lower pressures, a secondary pump is used, such as a diffusion pump or a sublimation pump (both must remain connected to a primary or "roughing" pump). There are two kinds of diffusion pumps. A mercury diffusion pump can reach 10 6 Torr, but the toxicity of mercury vapor has decreased its use dramatically. A silicone oil diffusion pump can reach 10-7 Torr. For even lower pressures, a Ti sublimation pump is used it can reach about 10 11 Torr. It is usually connected to a sorption primary pump. The ultimate low pressure attained in a laboratory on earth is about 10 13Torr. 

The body of these cells is connected to a dual primary and secondary pumping system. An initial primary pumping system is used to evacuate the reactive gases in order to avoid excess contamination of the secondary pumping system which can be used to obtain vacuums of approximately 10" mbar if required. 

The whole system for corrosion rate monitoring has been operating in a plant for testing PWR primary pumps, developed by ENEA and FIAT. The system comprises ... 

Apparatus. High performance liquid chromatographic separations were achieved on a binary gradient microbore HPLC systems primary pump (A) Model 305, secondary pump (B) Model 306, monomclric module Model 805, and a dynamic mixer Model 811C from Gilson Inc. (Middleton. Wl). Sample injections were achieved with a 20 pL loop on a Model EQ-36 injection valve from Valeo Instruments Co. Inc. (Houston, TX). A stainless steel Y-splitter also from Valeo was used in order to achieve a post-column split of the mobile phase Dow to the CLND. A Supelcosil LC-18S analytical HPLC column was purchased from SUPELCO Inc. (Bellefonte. PA). The Y-splitter was attached to the analytical column by a SLIPFREE connector, available from Keystone Scientific Inc. (Bellefonte, PA). Analyses of nor-dihydrocapsaicin, capsaicin and dihydrocapsaicin in spices as well... 

You suck a 1 cm air bubble through the Teflon tube up to 15 cm before the inlet valve of the primary pump head. 

The next important postulate of Mitchell s theory concerns the consumers of the energy produced by primary pumps and presupposes the presence in the organella membranes of secondary proton pumps which use the transmembrane proton flow for ATP synthesis and a number of other processes. Essential to this theory is the... 

What proved a triumph for Mitchell s hypothesis was the experiments involving simultaneous insertion of ATP synthtases and of one of the primary pumps.163 The synthesis of ATP was accomplished on liposomes. Addition of substances increasing the conductance of the membrane disturbed the coupling both in liposomes and in mitochondria. 

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