Abstract: Coated abrasive articles having spacer particles are formed by providing a production tool having a dispensing surface with a plurality of cavities, guiding the production tool past an abrasive particle feeder, dispensing shaped abrasive particles onto the dispensing surface and into the plurality of cavities of the production tool, guiding a resin coated backing sheet adjacent the production tool past a spacer particle feeder, and dispensing spacer particles onto the resin coated backing sheet and/or the production tool after the abrasive particle feeder prior to a deposit point for the shaped abrasive particles. The spacer particles are selected to have a thickness that is greater than a thickness of a resin coating of the resin coating backing sheet and a thickness and density once dispensed that are sufficient to substantially prevent the production tool from contacting the resin coated backing sheet at the deposit point.

Abstract: A repositionable abrasive disc mounting assembly comprises a backup pad and a clamp assembly. The backup pad has a rotational axis of use and a major surface with projections extending outwardly therefrom. The backup pad further comprises an inwardly facing centrally disposed first fastening member, and also an outwardly facing centrally disposed second fastening member. The clamp assembly comprises inner and outer clamp members for securing an abrasive disc. The inner clamp member comprises an inwardly facing centrally disposed third fastening member adapted to repositionably engage the second fastening member in a discrete number of rotational orientations. The inner clamp member further comprises an outwardly facing centrally disposed fourth fastening member. The outer clamp member comprises an inwardly facing centrally disposed fifth fastening member adapted to securely engage the fourth fastening member. A method of abrading a workpiece using the repositionable abrasive disc is also disclosed.

Abstract: A technique for in situ decontamination of an earth formation. High gas temperatures can be achieved at subsurface formations by supplying a fuel at a subsurface location, such as at the bottom of a wellbore. Pressurized air or gas preheated to a temperature of about 700.degree. F.-1200.degree. F. is supplied to the wellbore to ignite the fuel. The combustion heat produced by the fuel further heats the preheated gas to temperatures in the range of 1200.degree. F.-4500.degree., which heated gases are forced out of the borehole into the contaminated formation. Contaminants are thereby volatilized or oxidized and removed from the formation to the surface.

Abstract: A mobile air supply cart for use by personnel wearing respirators while working in hazardous environments. The cart supports two compressed air cylinders and has a handle and wheels, thereby facilitating transporting the air supply as the movements of the user require. A connector pin allows the cart to be separated into a base assembly and a frame assembly to which the cylinders are secured. In this configuration the cylinders can be carried through confined spaces. A piping system is mounted on the cart and regulates the pressure of the air supplied to the user. Valving allows the cylinder from which air is supplied to be switched out and the other cylinder to be switched in as the air is depleted in one cylinder without interrupting the supply of air to the user. A low pressure manifold on the cart allows several users to be supplied with air simultaneously. A coupling in the piping system allows the cylinders to recharged from a remote air supply while simultaneously supplying air to the user.

Abstract: A technique for decontaminating material, including disposing a grid network of perforated pipes on a base, and covering the same with contaminated soil. A barrier layer is laid on the contaminated material and provided with a vent port coupled to a vapor disposal unit via a suction system. A source of heated gas is coupled to the grid system to force heated air through the contaminated soil and vaporize the contaminants. A mobile decontamination system includes an insulated container having a top lid for loading contaminated material in the container, and an insulated back door for removing decontaminated material. Apertured pipes on the container floor convey a high temperature gas to the contaminated material to vaporize the contaminants. A suction system is coupled to a vapor outlet of the container to remove vaporized contaminants.

Abstract: A technique for in situ decontamination of an earth formation. High gas temperatures can be achieved at subsurface formations by supplying a fuel at a subsurface location, such as at the bottom of a wellbore. Pressurized air or gas preheated to a temperature of about 700.degree. F.-1200.degree. F. is supplied to the wellbore to ignite the fuel. The combustion heat produced by the fuel further heats the preheated gas to temperatures in the range of 1200.degree. F.-4500.degree., which heated gases are forced out of the borehole into the contaminated formation. Contaminants are thereby volatilized or oxidized and removed from the formation to the surface.

Abstract: Disclosed is in situ decontamination methods and apparatus for injecting a hot gas into boreholes formed in a contaminated soil area to vaporize the soil moisture and contaminants, and for collecting the vaporized contaminants at the surface of the soil. A burner heats pressurized gases and mixes the same with combustion gases for injection into the contaminated zone. A central collection system recovers the vaporized contaminants and couples such vapors to an on-site incinerator for disposal. Controlled heating of the injection gas is effective to sequentially remove different types of contaminants, as well as to provide in situ oxidation of other contaminants, while minimizing recondensation of the soil vapors. Wellbore casings are especially adapted for injecting the gas in predetermined patterns. In addition, a heater and incinerator assembly utilizes a single burner for both heating the dry gas and for incinerating the vapor contaminants.

Abstract: Disclosed is in situ decontamination methods and apparatus for injecting a hot gas into boreholes formed in a contaminated soil area to vaporize the soil moisture and contaminants, and for collecting the vaporized contaminants at the surface of the soil. A burner heats pressurized gases and mixes the same with combustion gases for injection into the contaminated zone. A central collection system recovers the vaporized contaminants and couples such vapors to an on-site incinerator for disposal. Controlled heating of the injection gas is effective to sequentially remove different types of contaminants, as well as to provide in situ oxidation of other contaminants, while minimizing recondensation of the soil vapors. Wellbore casings are especially adapted for injecting the gas in predetermined patterns. In addition, a heater and incinerator assembly utilizes a single burner for both heating the dry gas and for incinerating the vapor contaminants.