Abstract: The present invention utilizes two precious metals with two to five different metal-oxides in a layered matrix to convert CO, HCs, and NOx to CO2, and N2 by oxidation of two components and reduction of the other in a moderately high temperature gaseous environment containing excess oxygen.

Abstract: A process for forming catalysts by coating substrates with two or more catalytic components, which comprises the following sequence of steps. First, the substrate is infused with an adequate amount of solution having a starting material comprising a catalytic component precursor, wherein the thermal decomposition product of the catalytic component precursor is a catalytic component. Second, the excess of the solution is removed from the substrate, thereby leaving a coating of the catalytic component precursor on the surface of the substrate. Third, the coating of the catalytic component precursor is converted to the catalytic component by thermal decomposition. Finally, the coated substance is etched to increase the surface area. The first three steps are then repeated for at least a second catalytic component. This process is ideally suited for application in producing efficient low temperature oxidation catalysts.

Abstract: A means for detecting volatile organic compounds which utilizes a catalytic material to oxidize volatile organic compounds at temperatures substantially lower than the autoignition temperature of the compound. Because this reaction is exothermic, a thermistor in contact with the catalytic material is used to detect the heat evolved as volatile organic compounds are oxidized to carbon dioxide and water at the catalyst surface. Upon comparison to a reference thermistor, relative increases in the temperature of the sensing thermistor correspond positively with an increased concentration of volatile organic compounds and are thus used as an indicator of the presence of such compounds.

Abstract: A device and method are provided for measuring the thermal conductivity of rigid or flexible, homogeneous or heterogeneous, thin films between 50 &mgr;m and 150 &mgr;m thick with relative standard deviations of less than five percent. The specimen is sandwiched between like material, highly conductive upper and lower slabs. Each slab is instrumented with six thermocouples embedded within the slab and flush with their corresponding surfaces. A heat source heats the lower slab and a heat sink cools the upper slab. The heat sink also provides sufficient contact pressure onto the specimen. Testing is performed within a vacuum environment (bell-jar) between 10−3 to 10−6 Torr. An anti-radiant shield on the interior surface of the bell-jar is used to avoid radiation heat losses. Insulation is placed adjacent to the heat source and adjacent to the heat sink to prevent conduction losses. A temperature controlled water circulator circulates water from a constant temperature bath through the heat sink.

Abstract: Disclosed is a process for oxidizing volatile organic compounds to carbon dioxide and water with the minimal addition of energy. A mixture of the volatile organic compound and an oxidizing agent (e.g. ambient air containing the volatile organic compound) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

Abstract: A means for detecting carbon monoxide which utilizes an un-heated catalytic material to oxidize carbon monoxide at ambient temperatures. Because this reaction is exothermic, a thermistor in contact with the catalytic material is used as a sensing element to detect the heat evolved as carbon monoxide is oxidized to carbon dioxide at the catalyst surface, without any heaters or external heating elements for the ambient air or catalytic element material. Upon comparison to a reference thermistor, relative increases in the temperature of the sensing thermistor correspond positively with an increased concentration of carbon monoxide in the ambient medium and are thus used as an indicator of the presence of carbon monoxide.

Abstract: A catalyst for the combination of CO and O.sub.2 to form CO.sub.2 which includes a platinum group metal--e.g., platinum; a reducible metal oxide having multiple valence states--e.g., SnO.sub.2 ; and a compound which can bind water to its structure--e.g., silica gel. This catalyst is ideally suited for application to high-powered, pulsed, CO.sub.2 lasers operating in a sealed or closed-cycle condition.

Abstract: A catalyst for the combination of CO and O.sub.2 to form CO.sub.2 which includes a platinum group metal--e.g., platinum; a reducible metal oxide having multiple valence states--e.g., SnO.sub.2 ; and a compound which can bind water to its structure--e.g., silica gel. This catalyst is ideally suited for application to high-powered, pulsed, CO.sub.2 lasers operating in a sealed or closed-cycle condition.

Abstract: A quantity of reagent grade tin metal or compound, chloride-free, and high-surface-area silica spheres are placed in deionized water, followed by deaerating the mixture by boiling and adding an oxidizing agent, such as nitric acid. The nitric acid oxidizes the tin to metastannic acid which coats the spheres because the acid is adsorbed on the substrate. The metastannic acid becomes tin-oxide upon drying and calcining. The tin-oxide coated silica spheres are then placed in water and boiled. A chloride-free precious metal compound in aqueous solution is than added to the mixture containing the spheres, and the precious metal compound is reduced to a precious metal by use of a suitable reducing agent such as formic acid. Very beneficial results have been obtained using the precious metal compound tetraammine platinum(II) hydroxide.

Abstract: A method of exchanging rare-isotope oxygen for common-isotope oxygen in the top several layers of an oxide-containing catalyst is disclosed. A sample of an oxide-containing catalyst is exposed to a flowing stream of reducing gas in an inert carrier gas at a temperature suitable for the removal of the reactive common-isotope oxygen atoms from the surface layer or layers of the catalyst without damaging the catalyst structure. The reduction temperature must be higher than any at which the catalyst will subsequently operate. Sufficient reducing gas is used to allow removal of all of the reactive common-isotope oxygen atoms in the top several layers of the catalyst. The catalyst is then reoxidized with the desired rare-isotope oxygen in sufficient quantity to replace all of the common-isotope oxygen that was removed.

Abstract: A method for the reactivation of a tin oxide-containing catalyst of a CO.sub.2 laser is provided. First, the catalyst is pretreated by a standard procedure. When the catalyst experiences diminished activity during usage, the heated zone surrounding the catalyst is raised to a temperature which is the operating temperature of the laser and 400.degree. C. for approximately one hour. The catalyst is exposed to the same laser gas mixture during this period. The temperature of the heated zone is then lowered to the operating temperature of the CO.sub.2 laser.

Abstract: A process of preparing a new contact lens material that is gas permeable, surface wettable, and relatively hard is disclosed. Also disclosed are contact lenses made of this new material, which are comfortable to wear. The new contact lens material is the copolymerization product of a reaction mixture comprising: (1) styrene or a ring substituted styrene; (2) a vinyl alcohol ester such as vinyl acetate; (3) a polyethylene glycol ester such as pentaethyleneglycol monomethacrylate; (4) a substituted polysiloxane such as dimethyl polysiloxane or a substituted silane; and, optionally, (5) a cross-linking agent such as divinyl benzene.

Abstract: A new contact lens material that is gas permeable, surface wettable, and relatively hard is disclosed. Also disclosed are contact lenses made of this new material, which are comfortable to wear. The new contact lens material is the copolymerization product of a reaction mixture comprising: (1) styrene or a ring substituted styrene; (2) a vinyl alcohol ester such as vinyl acetate; (3) a polyethylene glycol ester such a pentaethyleneglycol monomethacrylate; (4) a substituted polysiloxane such as dimethyl polysiloxane or a substituted silane; and, optionally, (5) a cross-linking agent such as divinyl benzene.