1. A propulsion system comprising:
a rocket engine;
at least one propellant tank fluidically coupled to the rocket engine;
a coolant tank configured to hold a coolant;
a first heat exchanger thermally coupled to the rocket engine and fluidically coupled to the coolant tank; and
a second heat exchanger thermally coupled to the propellant tank and fluidically coupled to the first heat exchanger,
wherein the coolant flows from the coolant tank to the first heat exchanger, and
wherein the coolant flows from the first heat exchanger to the second heat exchanger.
2. The propulsion system of claim 1, further comprising a third heat exchanger disposed inside the propellant tank, wherein the third heat exchanger is configured to exchange heat between a propellant withdrawn from the tank for combustion and the propellant disposed inside the tank.
3. The propulsion system of claim 1, further comprising a pump configured to return at least a portion of the coolant from the second heat exchanger to the coolant tank.
4. The propulsion system of claim 1, wherein at least a portion of the coolant from the second heat exchanger flows to the rocket engine.
5. The propulsion system of claim 4, wherein the coolant comprises a combustible material and is combusted in the rocket engine.
6. The propulsion system of claim 4, wherein the coolant comprises a non-combustible material and is injected into the rocket engine.
7. The propulsion system of claim 1, wherein at least a portion of the coolant from the second heat exchanger is vented overboard.
8. A propulsion system comprising:
a rocket engine;
a propellant tank fluidically coupled to the rocket engine and configured to hold a pressurized propellant;
a coolant tank configured to hold a coolant;
a first heat exchanger thermally coupled to the rocket engine and fluidically coupled to the coolant tank;
a second heat exchanger thermally coupled to the propellant tank and fluidically coupled to the first heat exchanger; and
a third heat exchanger disposed inside the propellant tank and configured to thermally couple a propellant withdrawn from the tank for combustion to a propellant disposed inside the tank;
wherein the coolant flows from the coolant tank to the first heat exchanger and through the first heat exchanger to cool the rocket engine,
wherein the propellant withdrawn from the propellant tank receives heat from the propellant disposed inside the tank through the third heat exchanger to convert to a gaseous propellant when withdrawn from the propellant tank as a liquid propellant, and
wherein the coolant flows from the first heat exchanger to the second heat exchanger and through the second heat exchanger to heat the propellant disposed inside the propellant tank.
9. The propulsion system of claim 8, further comprising a pump configured to return at least a portion of the coolant from the second heat exchanger to the coolant tank.
10. The propulsion system of claim 8, wherein at least a portion of the coolant from the second heat exchanger flows to the rocket engine.
11. The propulsion system of claim 10, wherein the coolant comprises a combustible material and is combusted in the rocket engine.
12. The propulsion system of claim 10, wherein the coolant comprises a non-combustible material and is injected into the rocket engine.
13. The propulsion system of claim 8, wherein at least a portion of the coolant from the second heat exchanger is vented overboard.
14. A method of cooling a rocket engine having a propellant tank, the method comprising:
withdrawing propellant from the propellant tank wherein the withdrawn propellant is thermally coupled to the propellant disposed inside the propellant tank, the withdrawing causing the withdrawn propellant to receive heat from the propellant disposed in the propellant tank to convert to a gaseous propellant when the withdrawn propellant is in a liquid form;
cooling a rocket engine with a coolant, the cooling of the rocket engine causing heating of the coolant; and
transferring heat from the heated coolant to the propellant disposed in the propellant tank so that a pressure of the propellant disposed in the propellant tank is maintained.
15. The method of claim 14, wherein the cooling comprises transferring the coolant from a coolant tank to a first heat exchanger thermally coupled to the rocket engine to cool the rocket engine, and transferring the coolant from the first heat exchanger to a second heat exchanger thermally coupled to the propellant tank to heat the propellant tank.
16. The method of claim 15, further comprising returning at least a portion of the coolant from the second heat exchanger to the coolant tank.
17. The method of claim 15, further comprising transferring at least a portion of the coolant from the second heat exchanger to the rocket engine.
18. The method of claim 17, wherein the coolant comprises a combustible material and further comprising combusting the coolant in the rocket engine.
19. The method of claim 17, wherein the coolant comprises a non-combustible material and further comprising injecting the coolant into the rocket engine.
20. The method of claim 15, further comprising venting at least a portion of the coolant from the second heat exchanger overboard.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1: A metal nanoparticle composite, comprising:
(A) a star-shaped polymer comprising a central core and arms bonded to the central core,
wherein the arms comprise a repeating unit represented by formula (1):
and a repeating unit represented by formula (2):
wherein R1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R2 represents a methyl group or an ethyl group, and k represents an integer from 1 to 10; and
(B) metal nanoparticles supported thereon.
2: The metal nanoparticle composite according to claim 1,
wherein the metal nanoparticles comprise at least one metal element selected from the group consisting of gold, silver, and copper.
3: The metal nanoparticle composite according to claim 1,
wherein the arms comprise a polymer chain comprising a repeating unit represented by the formula (1) and a polymer chain comprising a repeating unit represented by the formula (2).
4: The metal nanoparticle composite according to claim 1, wherein the arms comprise a polymer chain comprising a block body of a repeating unit represented by the formula (1) and a repeating unit represented by the formula (2).
5: The metal nanoparticle composite according to claim 1, wherein the star-shaped polymer has a lower limit critical solution temperature in an aqueous medium.
6: A metal nanoparticle dispersion liquid, comprising:
the metal nanoparticle composite according to claim 1, and an aqueous medium.
7: The metal nanoparticle dispersion liquid according to claim 6, wherein the aqueous medium is at least one selected from the group consisting of water, an alcohol, an aliphatic ketone, an aliphatic polyhydric alcohol, a glycol derivative, and a pyrrolidone.
8: The metal nanoparticle dispersion liquid according to claim 6, further comprising:
at least one water-soluble resin selected from the group consisting of polyvinyl alcohol, a modified polyvinyl alcohol-based resin, polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, and a cellulose ether-based resin.
9: A method for producing a metal nanoparticle composite, the method comprising:
(a) bringing a star-shaped polymer comprising a central core and arms bonded to the central core into contact with at least one selected from the group consisting of a metal salt and a metal complex salt in an aqueous medium, and adsorbing at least one selected from the group consisting of a metal ion and a metal complex ion to the star-shaped polymer,
wherein the arms comprise a repeating unit represented by formula (1):
and a repeating unit represented by formula (2):
wherein R1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R2 represents a methyl group or an ethyl group and k represents an integer from 1 to 10; and
(b) bringing a reducing agent into contact with at least one selected from the group consisting of a metal ion and a metal complex ion that are adsorbed in the bringing (a).
10: The method according to claim 9,
wherein the at least one selected from the group consisting of a metal salt and a metal complex salt comprises at least one metal element selected from the group consisting of gold, silver, and copper.
11: The method according to claim 9, wherein the reducing agent comprises at least one selected from the group consisting of an alkali metal borohydride, a hydrazine compound, citric acid, a citric acid salt, succinic acid a succinic acid salt, ascorbic acid, and a ascorbic acid salt.
12: The method according to claim 9, wherein the method further comprises:
(c) heating an aqueous medium comprising the metal nanoparticle composite obtained in the bringing (b) to a temperature higher than a lower limit critical solution temperature of the star-shaped polymer, separating an aggregate phase comprising the metal nanoparticle composite and a liquid phase comprising the aqueous medium, and collecting the aggregate phase; and
(d) dispersing the aggregate phase collected in the heating (c) in an aqueous medium that is identical with or different from the aqueous medium used in the bringing (a) at a temperature lower than the lower limit critical solution temperature of the star-shaped polymer
wherein the star-shaped polymer has the lower limit critical solution temperature in the aqueous medium.
13: The method according to claim 9, wherein the aqueous medium comprises at least one selected from the group consisting of water, an alcohol, an aliphatic ketone, an aliphatic polyvalent alcohol, a glycol derivative, and a pyrrolidone.
14: A composition for forming a metal nanoparticle-dispersed film, the composition comprising:
the metal nanoparticle composite according to claim 1, and
at least one selected from the group consisting of a crosslinkable compound and a film-forming resin.
15: The composition according to claim 14,
wherein the film-forming resin comprises at least one selected from the group consisting of a water-soluble resin and an acrylic resin.
16: A metal nanoparticle-dispersed film obtained from the composition according to claim 14.