TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Process: The process further involves heating the mixture to 313-773 (preferably 373-473, especially 393-453) kelvin. Preferred Composition: In the process, the endothermic composition generates a gas comprising carbon dioxide or hydrogen. In the process, the endothermic composition comprises a carbonate compound; a metal hydride; a mixture comprising at least one chemical hydride (H1) and at least one alkali or alkaline earth metal amide compound; or at least partially hydrogenated pi-conjugated analogue. Preferred Components: In the process, the at least one chemical hydride (H1) is selected from boron hydrides, ionic hydride salts, and aluminum hydrides (preferably lithium aluminum hydride, BH3NH3, lithium borohydride, sodium borohydride or lithium hydride). The boron hydride is selected from borohydride salts of formula (M(BH4)n), triborohydride salts of formula (M(B3H8)n), decahydrodecaborate salts of formula (M2(B10H10)n), tridecahydrodecaborate salts of formula (M(B10H13)n), dodecahydrododecaborate salts of formula (M2(B12H12)n), and octadecahydroicosaborate salts of formula (M2(B20H18)n) (preferably decaborane(14)(B10H14) and tetraborane(10) (B4H10)). The ammonia borane is selected from compounds of formula NHxBHy and NHxRBHy (preferably NH3B3H7 and NH(CH3)2BH3). The ionic hydride is selected from hydrides of alkali metals, alkaline earth metals, and zinc metal of formula M'Hn'. The aluminum hydride is selected from alane and aluminum hydride salts. The aluminum hydride salts are of formula M(AlH4)n. The at least one water surrogate source is selected from hydroxide salts of alkali and alkaline earth metals, and the hydroxide compounds of Group 13 elements; alkali metal dihydrogen phosphate salts; alkali metal dihydrogen citrate salts; sulfate salts of alkali and alkaline earth metals; phosphate salts of alkali and alkaline earth metals; compounds of formula (M1)y'(OpX(OH)q)n1; alcohols; polymeric alcohols; silicates; silica sulfuric acid; acid chloride compounds; hydrogen sulfide and amines; carbohydrates borate salts; carboxylic acids; bicarbonate salts; or allylic alcohols (preferably aluminum hydroxide, mannitol, sorbitol or fructose). The first chemical hydride is BH3NH3, a second chemical hydride is lithium aluminum hydride. In the system, the endothermic gas generation composition comprises a mixture of at least one chemical hydride (preferably NaBH4, LiBH4, KBH4, MgH2, LiH, NaH, KH, LiAlH4 or NaAlH4) and at least one metal nitrogen hydrogen compound (preferably alkali and alkaline earth metal amides and imides containing LiNH2, NaNH2, KNH2, CsNH2, Mg(NH2)2, Ca(NH2)2, Li2NH, Na2NH, K2NH, MgNH and CaNH); a metal hydride (preferably NaAlH4, Na3AlH6, LiNH2, MgH2, LaNi5, and mixtures of LiBH4-MgH2; or AB-, AB2-, AB5-, and A2B-type metal hydrides, including hydrides of metal alloys of titanium, iron, manganese, nickel, and chromium such as Mg2Ni, LaNi5, or FeTi); a carbonate compound (preferably magnesium carbonate); a mixture of at least one chemical hydride (H1) and at least one water surrogate source. In the system, the mixture comprises LiH and LiNH2 combined in a molar ratio of about 2:1, LiAlH4 and LiNH2 combined in a molar ratio of about 2:1, LiAlH4 and LiNH2 combined in a molar ratio of about 1:2, MgH2 and LiNH2 combined in a molar ratio of about 1:2 or LiH and Mg(NH2)2 combined in a molar ratio of about 4:1.M=alkali metal cation, alkaline earth metal cation, aluminum cation, zinc cation or ammonium cation;n=charge of the cation;x and y=1-4 and do not have to be the same;R=methyl or ethyl group;M'=cation selected from alkali metal cations, alkaline earth metal cations or zinc(II);n'=charge of the cation;M1=alkali metal or NH4;q=0-3;p=0-3;y'=valence of the anion (OpX(OH)q);n1=valence of M1;X=S, P or Se.Preferred System: The each gas generation pair further comprises an initiation element in contact with the first pellet of the exothermic hydrogen generation composition; and a third pellet of an endothermic gas generation composition in contact with the first pellet of the exothermic hydrogen generation composition. The system further comprises a spacer between the gas generation pairs. The spacer is configured to permit hydrogen gas to pass through it. The first pellet of the exothermic hydrogen generation composition and the second pellet of the endothermic gas generation composition have the same size or different sizes. Preferred Fuel Cartridge: In the fuel cartridge, each fuel compartment contains only one of the endothermic gas generation composition and the exothermic hydrogen generation composition; or both of the endothermic gas generation composition and exothermic hydrogen generation composition. The exothermic hydrogen generation composition is in the form of a first pellet, the endothermic gas generation composition is in the form of a second pellet, and the first pellet and the second pellet in contact provide a gas generation pair. The initiation element is disposed between the first pellet and the second pellet; and touches the side of the first pellet. The fuel cartridge comprises several gas generation pairs, where each of the gas generation pair is separated from one another by a spacer configured to permit hydrogen gas to pass through it. The cartridge, the gas generation pair further includes a third pellet of an endothermic gas generation composition in contact with the first pellet of the exothermic hydrogen generation composition. The fuel compartments are arranged in a several layers arranged such that the first pellet comprising the exothermic hydrogen generation composition in a first layer is juxtaposed to the second pellet of the endothermic gas generation composition in a second layer. In the fuel cartridge, the aluminum hydroxide is present in molar excess relative to the lithium aluminum hydride; and the lithium aluminum hydride is present in molar excess relative to the aluminum hydroxide. The initiation element is selected from resistance heaters, spark igniters, nickel-chromium resistance wires, and heat exchangers. The initiation element is a wire or a plate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: In the system, the endothermic gas generation composition comprises at least partially hydrogenated pi-conjugated organic system (preferably hexabenzocoronene, rubicene, picene, ovalene, coronene, perylene, pyrene, phenanthrene, and anthracene, indolylmethane, indolocarbazoles, N-alkylcarbozoles, fluorene, indene, acenaphthylene, polyfurans, polypyrroles, polyindoles, and polycarbazoles).    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The spacer is comprised of a material selected from glass, ceramics, cellulose, minerals, xerogels and aerogels. The porous walls are comprised of a material selected from glasses, ceramics, plastics, polymers, aerogels, and xerogels. The porous walls have a porosity of at least 10%. EXAMPLE - No suitable example is given.