Abstract: Passive on-board aircraft cooling systems are provided with an evaporator/receiver in heat-exchange relationship with at least one heat source on board the aircraft, the evaporator/receiver containing a liquid phase working fluid which changes state to a vapor phase working fluid in response to heat transfer therefrom from the at least one heat source. First and second condensers are fluid-connected to the evaporator/receiver for receiving vapor phase working fluid from the evaporator/receiver. At least a portion of the vapor phase working fluid transferred to the first and second condensers is condensed by heat transfer between the first and second condensers and aircraft-external unpressurized and aircraft-internal pressurized air supply streams, respectively, to thereby form liquid phase working fluid which returns to the evaporator/receiver by virtue of the fluid connection with the first and second condensers.

Abstract: The metallurgical composition comprises a main particulate metallic material, for example iron or nickel, and at least one alloy element for hardening the main metallic material, which form a structural matrix; a particulate solid lubricant, such as graphite, hexagonal boron nitride or mixture thereof; and a particulate alloy element which is capable of forming, during the sintering of the composition conformed by compaction or by injection molding, a liquid phase, agglomerating the solid lubricant in discrete particles. The composition may comprise an alloy component to stabilize the alpha-iron matrix phase, during the sintering, in order to prevent the graphite solid lubricant from being solubilized in the iron. The invention further refers to the process for obtaining a self-lubricating sintered product.

Abstract: The process comprises the steps of: mixing a load of oxide ceramic material particles (10) with a load of space holder particles (20), defined by graphite and/or amorphous carbon; compacting the mixture formed by ceramic material particles (10) and space holder particles (20), to form a compact body (E); and sintering said compact body (E), so that the ceramic material particles (10) form sintering contacts with each other, whereas the carbon of the space holder particles (20) is removed by the reaction with the oxygen in the sintering medium, to form open secondary pores (II), by eliminating the space holder particles (20). The metallurgic composition comprises the mixture of the ceramic material particles (10) with the space holder particles (20).

Abstract: The plasma reactor comprises a reaction chamber (23) connectable to a source of ionizable gases (25) and to a heating device (80), said reactor (10) being subjected to the phases of heating (A), cleaning (L) and/or surface treatment (S), cooling (R), unloading (D) and loading (C) of metallic pieces (1). The installation comprises: at least two reactors (10), each being selectively and alternately connected to: the same source of ionizable gases (25); the same vacuum source (60); the same electrical energy source (50); and to the same heating device (80), the latter being displaceable between operative positions, in each of which surrounding laterally and superiorly a respective reactor (10), while the latter is in its heating phase (A) and cleaning phase (L) and/or in the surface treatment phase (S) of the metallic pieces (1).

Abstract: A process for the synthesis of nanostructured metallic hollow spherical particles, in which the metal is deposited onto sacrificial masks formed in a polymeric colloidal solution by the electroless autocatalytic deposition method. Deposition releases only gaseous products (N2 and H2) during the oxidation thereof, which evolve without leaving contaminants in the deposit. The particulate material includes nanostructured metallic hollow spherical particles with average diameter ranging from 100 nm to 5 ?m and low density with respect to the massic metal. A process for compacting and sintering a green test specimen are also described.

Abstract: The metallurgical composition includes a main particulate metallic material, for example iron or nickel, and at least one alloy element for hardening the main metallic material, which form a structural matrix; a particulate solid lubricant, such as graphite, hexagonal boron nitride or mixture thereof; and a particulate alloy element which is capable of forming, during the sintering of the composition conformed by compaction or by injection molding, a liquid phase, agglomerating the solid lubricant in discrete particles. The composition may include an alloy component to stabilize the alpha-iron matrix phase, during the sintering, in order to prevent the graphite solid lubricant from being solubilized in the iron. The invention further refers to a self-lubricating sintered product, obtained from the composition, and to the process for obtaining said product.

Abstract: The process comprises the steps of: mixing a load of oxide ceramic material particles (10) with a load of space holder particles (20), defined by graphite and/or amorphous carbon; compacting the mixture formed by ceramic material particles (10) and space holder particles (20), to form a compact body (E); and sintering said compact body (E), so that the ceramic material particles (10) form sintering contacts with each other, whereas the carbon of the space holder particles (20) is removed by the reaction with the oxygen in the sintering medium, to form open secondary pores (II), by eliminating the space holder particles (20). The metallurgic composition comprises the mixture of the ceramic material particles (10) with the space holder particles (20).

Abstract: The process basically comprises: dissolving a lamellar disulphide, as a source of the solid lubricant, in an aqueous solvent, forming a first aqueous solution; dissolving a reducing agent, as hydroxylamine, sodium hypophosphite or sodium borohydride, in an aqueous solvent, forming a second aqueous solution; mixing the first and second aqueous solutions, forming a third aqueous solution; neutralizing the pH of the third aqueous solution; dissolving a sulphur source, in an aqueous solvent, forming a fourth aqueous solution; mixing the third and fourth aqueous solutions, forming a fifth aqueous solution, which is contained and heated in an autoclave; cooling the fifth aqueous solution to the room temperature; and removing, from the autoclave, the nanoparticles in powder form.

Abstract: The present invention provides a refrigeration system for compact equipment, particularly of the type including electronic circuits and internally provided with a heat source to be cooled, said refrigeration system including a heat dissipation device mounted in the equipment and including a heat absorbing portion, which absorbs heat from the heat source, and a heat dissipation portion accessible from the outside of the equipment and which releases the heat to the exterior of the equipment; and an auxiliary refrigeration circuit external to the equipment and having: a heat absorbing means to be selectively coupled to the heat dissipation portion so as to receive therefrom, by conduction, at least part of the heat received from the heat source and dissipated by said heat dissipation portion; and a heat dissipation means which releases the heat to the environment external to the equipment.

Abstract: A refrigeration system includes a compressor; a condenser connected to a first inlet of a separator which has: a vapor outlet connected to the compressor and a liquid outlet connected to an evaporator; a selecting valve having: a first vapor inlet connected to the evaporator; a second vapor inlet connected to the separator; and a vapor outlet connected to the compressor, the selecting valve being operated to selectively and alternatively communicate its first and second vapor inlets with its vapor outlet, so as to allow the compressor to draw vapor from the separator and from the evaporator; and a control unit for controlling the operation of the selecting valve.

Abstract: Cooling system for reciprocating compressors comprising an atomizing nozzle (1) that supplies an atomized lubricating fluid inside the compressor cylinder (2), a heat exchanger (6) intended for cooling the lubricating fluid to be atomized at the nozzle (1), a fluid separator (5) for separating a mixture of cooling fluid and lubricating fluid and directing the lubricating fluid back from the system, and a blocking element (7) arranged between the atomizing nozzle (1) and the heat exchanger (6) to prevent the buildup of lubricating fluid in the cylinder. Reciprocating compressor having the cooling system as described.

Abstract: A self-contained, portable refrigeration unit having a construction arrangement which enables it to be compatible with several models, types and variations of refrigeratable compartments. This refrigeration unit is represented by a refrigeration module (1) capable of being removably fitted into a refrigeratable compartment, comprising a first housing (100) and a second housing (200) associated with each other. The first housing (100) is in contact with the inside of the refrigeratable compartment and the second housing (200) is in contact with the outside of the refrigeratable compartment, and in some embodiments of the present invention, the first housing (100) is capable of moving in relation to the second housing (200). The first housing (100) interfaces the refrigeration module (1) with the inside of the refrigeratable compartment. The second housing (200) interfaces the refrigeration module (1) with the outside of the refrigeratable compartment.