A method of evaluating the performance of a control system using a computerized device includes calculating a ratio of a first area and a second area associated with a peak value of a signal associated with the control system, comparing the ratio with a predetermined value for the ratio, determining a cause of oscillation in the control system based on the comparison of the ratio with the predetermined value for the ratio, and providing a diagnosis of the cause of oscillation in the control system.

Method of and apparatus for evaluating the performance of a control system

A regenerable high capacity carbon dioxide (CO2) sorbent is operated to remove substantially all of the CO2 present in either a dry, or a humid environment. The sorbent is an amine compound which is composed predominantly of secondary amine groups, and includes one or more functional nitrile groups. Primary and tertiary amine groups form a minor percent of the sorbent. The reaction product of tetraethylenepentamine (TEPA) and acrylonitrile (AN), which reaction product will be referred to hereinafter as “TEPAN” is a preferred sorbent. The addition of one or more nitrile functional groups to TEPA by reason of the reaction between AN and TEPA converts most of the primary amines in TEPA to secondary amines in TEPAN. We have discovered that the presence of predominantly secondary amines in the sorbent enhances the regenerable cyclic CO2 absorption capacity of the sorbent by more than two and one-half times, as compared to a TEPA sorbent bed; and the use of TEPAN as the sorbent bed also significantly reduces amine volatility to low levels which are immeasurable. The sorbent bed of this invention is also easily regenerable.

Sorbent system and method for absorbing carbon dioxide (CO2) from the atmosphere of a closed habitable environment

Pressure-sensitive adhesive (PSA) compositions containing a crystalline polymeric additive having an Mw of less than 25,000 and a melting point (Ta) greater than 23° C, preferably 30° to 60° , and PSA composites of a backing, preferably a flexible backing, with such a PSA composition coated thereon The presence of the additive causes the PSA to lose adhesive strength when heated to Ta The base resin of the PSA is preferably a polyacrylate or a styrene/butadiene copolymer The additive, which is preferably present in amount 1 to 35%, eg 5 to 30%, is preferably a side chain crystallizable (SCC) polymer

Pressure-sensitive adhesives

LOVA gun propellants are formed from a thermoplastic elastomer and particulates of high-energy oxidizers, e.g., RDX and HMX.

Thermoplastic elastomer-based low vulnerability ammunition gun propellants

An effective neutral polymeric bonding agent (NPBA) is disclosed for a polar filler such as crystals of a nitramine (HMX or RDX, for example) dispersed in a polar binder, such as energetic binders containing nitro- and nitrato-plasticizers. The exceptional strength of the propellant composite of this invention is derived from a NPBA tailored to conform to criteria found to take advantage of the surface and absorption properties of the system so as to inculcate such strength. In particular, an interpolymer of acrylonitrile, methylacrylate and hydroxyethylacrylate can be tailored to provide a NPBA for a submix of a OH-terminated prepolymer and polar nitro- or nitratoplasticizers, such as nitroglycerine, which have solubility parameters in about the same range. Typically the submix includes HMX, RDX, ammonium perchlorate and the like along with fuel particles such as aluminum, boron, and the like.

Filler reinforcement of polyurethane binder using a neutral polymeric bonding agent

A process is disclosed by which thermoplastic elastomers may be utilized torepare melt-formable composite rocket propellants. The thermoplastic elastomer is dissolved in a volatile organic solvent, the other propellant ingredients are mixed in, and the volatile organic solvent is evaporated. The dried propellant is melt-formed to final shape by molding or extruding above the melting point of the elastomer. An example of a usable thermoplastic elastomer is a block copolymer comprised of about 5 to about 20 weight percent styrene and of about 80 to 95 weight percent diene. The formed grain can be reclaimed by melting or dissolution in an organic solvent for reuse of the propellant ingredients.

Thermoplastic composite rocket propellant

The reaction products formed from tri-functional aziridinylphosphine oxidesr their derivatives reacted with monofunctional carboxylic acids, the tri-aziridinyl derivatives of triazine, the tri-aziridinyl derivatives of benzenetriacyl, the aziridine compound N-phenethylaziridine, and selected alkyl diaziridine compounds are representive of the aziridine compounds which are utilized in isocyanate curable composite propellant compositions to extend usable pot life required for mixing and processing of the specified compositions. The compositions are comprised of a binder of hydroxy terminated liquid polymer systems, (e.g. hydroxy terminated polybutadiene and the like) selected plasticizers, optional metal fuel, and the inorganic oxidizer, ammonium perchlorate, that is substantially of very fine particle size (less than 20 microns).

Pot life extension of isocyanate cured propellants by aziridine compounds

A new combination of bonding agents when employed in hydroxy-terminated pbutadiene propellant compositions yields greatly improved high temperature aging characteristics and greatly improved low temperature physical properties for the compositions. The combination or bonding agent system consists of MT4 (reaction product of 2.0 moles of tris 1(2 methylaziridinyl)phosphine oxide, 0.7 mole adipic acid, and 0.3 mole tartaric acid); HX752 (bis isophthaloyl 1(2 methyl)aziridine); and BIDE (butyliminodiethanol) in a weight percent range of the propellant composition of 0.10% to 0.20%, 0.10% to 0.20% and 0.02% to 0.05% respectively.

Bonding agent system for improved propellant aging and low temperature physical properties

A process is disclosed for improving the mechanical properties and procesility of thermoplastic composite propellants achieved by incorporation in the propellant of from about 0.1% to 1.0% of an organic titanate of the general formula Ti(OR)4, where R represents a common alkyl group. The process comprises dissolving in an excess amount of a volatile organic solvent a thermoplastic elastomer which consists of hard segments having substantially crystalline properties and soft segments having substantially amorphous properties. The hard segments impart rigid properties to a solid propellant composition with which it is combined, and the soft segments imparting rubbery properties to a solid propellant composition with which it is combined. The Ti(OR)4 functions as a medium between the surface of the ammonium perchlorate (AP) oxidizer and the thermoplastic elastomer to improve processability and to provide a bonding substrate to enhance the adhesive bond between the AP and the thermoplastic elastomer. After solvent removal, the propellant pellets are heat formed in a mold, the mold is cooled, and the molded product is released in the form of a solid propellant grain.

Tetra-alkyl titanates as bonding agents for thermoplastic propellants

The polyamine compound, TEPAN, a partially cyanoethylated tetraethylene pamine, is reacted with a selected ammonium salt to form an adduct of TEPAN and the selected ammonium salt. The ammonium salt is selected from ammonium perchlorate (AP), ammonium nitrate (AN), ammonium sulfate (AS), and ammonium formate (AF). The process for preparation of the adduct comprises reacting a water solution of the selected ammonium salt with TEPAN while stirring at room temperature. A TEPAN-glycidol derivative product is also reacted with the selected oxidizer salt to form an adduct of the TEPAN-glycidol derivative product. The disclosed adducts (having adduct ratios of 1.0 to 1.8 equivalents of ammonium salt per mole of TEPAN or TEPAN-glycidol derivative product, TEPANOL) improve mechanical properties and processiblity of composite propellant composition containing about 88 weight percent solids (ammonium perchlorate, aluminum, and Fe 2 O 3 catalyst), a binder of hydroxy-terminated polybutadiene and dioctyladipate cured with a mixture of isophorone diisocyanate and a trifunctional isocyanate. Mechanical properties, especially strain at maximum stress at -40° C. are substantially improved. The processing time, particularly the mix cycle time, is shortened because of the amine salt bonding agent eliminating or minimizing in situ ammonia generation during the incorporation and mixing of ammonium perchorate into the propellant mix.

Henry C. Allen

Papers

Thermoplastic composite rocket propellant

Pot life extension of isocyanate cured propellants by aziridine compounds

Bonding agent system for improved propellant aging and low temperature physical properties

Tetra-alkyl titanates as bonding agents for thermoplastic propellants

Amine salts as bonding agents