Dual agent systems

Any advantages of a dual agent system, e.g. water and carbon dioxide. 

Self contained dual agent systems, (foam/water and dry chemical), are provided for manual fire fighting efforts against three dimensional pressure leaks and large diameter pool fires. The design affords fast fire knockdown, extinguishment and sealant against re-flash. A skid... 

Dual Agent Systems Aircraft Operations (Fixed wing and rotary)... 

Dual Agent Systems Aircraft operations (fixed and rotary wing)... 

Sodium bicarbonate- and borax bicarbonate-based dry chemicals were among the first dry agents used in portable fire extinguishers. About 1960, the sodium bicarbonate dry chemical was modified to make it compatible with protein-based, low-expansion foam to create a dual agent extinguishing system. Shortly thereafter, the more effective Purple K based extinguishers replaced sodium bicarbonate extinguishers. 

The problems associated with the multifunctional curing agents for CTPB and the resultant aging behavior of the cured polymers have led to a practical solution for curing binders and propellants—i.e., using mixed aziridines or a mixture of an aziridine and an epoxide. Such mixtures, when appropriately balanced, usually provide satisfactory mechanical behavior and high temperature stability. In dual curing systems such as MAPO and BITA or MAPO and a suitable multifunctional epoxide,... 

To solve this problem, Pericas and co-workers have introduced a dual catalytic system consisting of a chiral amino alcohol 2, to control the enantioselectivity of the addition process, and a bulky silylating agent, to further activate the inline substrate (Scheme 1) [7]. When the 2/TIPSC1 system was used to promote the addition to imines derived from aromatic aldehydes, the addition reactions took place with good yield (63-75%) and high enantioselectivities (72-91%). Even in this case, a substoichiometric amount of chiral amino alcohol is required for a satisfactory result. 

The excipients chosen, their concentration, and the characteristics that can influence the drug product performance (e.g., stability and bioavailability) or manufacturability should be discussed relative to the respective function of each excipient. Compatibility of excipients with other excipients, where relevant (e.g., combination of preservatives in a dual preservative system), should be established. The ability of excipients (e.g., antioxidants, penetration enhancers, disintegrants, and releasecontrolling agents) to provide their intended functionality, and the intended drug product shelf life that is needed for performance throughout, should also be demonstrated. The information on excipient performance can be used, as appropriate, to justify the choice and quality attributes of the excipient, and to support the justification of the drug product specification. Information to support the safety of excipients, when appropriate, should be cross-referenced. 

In 2011, Jacobsen and coworkers developed a dual catalyst system consisting of a chiral primary amine-thiourea and an achiral thiourea for the intramolecular [5-1-2] cycloaddition based on oxidopyiylium intermediates (Scheme 19.57). This cooperative catal)4ic system provided easy access to tricyclic structures in moderate yields (37-77%) and good to high enantioselectivities (80-95% enantiomeric excess). Schreiner s thiourea 8 is proposed to be a carboxylate-binding agent, acting in cooperation with primary amine-thiourea 50. 

To control smog, automobiles are now provided with catalytic converters. CO and hydrocarbons are oxidized to CO2 and H2O in the presence of an oxidation catalyst such as platinum or palladium metal. NO must be reduced to N2, and this requires a reduction catalyst. A dual-catalyst system uses both types of catalysts. Alternatively, the air-fuel ratio of the engine is set to produce some CO and unburned hydrocarbons these then act as reducing agents to reduce NO to N2. 

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