Abstract: A method of operating a power tool having a motor and a controller is provided. The method includes: receiving a position of a variable-speed input mechanism mounted on the power tool; determining a target speed of the motor corresponding to the position of the variable-speed input mechanism; determining an underspeed threshold corresponding to the target speed; determining a rotational speed of the motor; and interrupting a supply of power to the motor if the rotational speed of the motor is less than the underspeed threshold.

Abstract: A method of operating a power tool having a motor and a controller is provided. The method includes: receiving a position of a variable-speed input mechanism mounted on the power tool; determining a target speed of the motor corresponding to the position of the variable-speed input mechanism; determining an underspeed threshold corresponding to the target speed; determining a rotational speed of the motor; and interrupting a supply of power to the motor if the rotational speed of the motor is less than the underspeed threshold.

Abstract: A composite membrane comprises an inorganic support having interstices and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof. The support is preferably a woven metal mesh, with the films substantially coplanar with the support. The films may be formed by applying a suspension of refractory particles in a polymer solution to bridge the interstices of the support, and heating the films to partly sinter the particles. Since the films are in compression at ambient temperature, any cracks that may be formed by damage to the composite membrane tend not to propagate.

Abstract: A composite membrane comprises an inorganic support having interstices and porous inorganic films of sintered non-metallic particles carried by the support and bridging the interstices thereof. The support is preferably a woven metal mesh, with the films substantially coplanar with the support. The films may be formed by applying a suspenion of refractory particles in a polymer solution to bridge the interstices of the support, and heating the films to partly sinter the particles. Since the films are in compression at ambient temperature, any cracks that may be formed by damage to the composite membrane tend not to propagate.

Abstract: A composite membrane comprises a porous metal support and at least one porous inorganic film of sintered non-metallic particles carried by the support and overlying a surface thereof. The film is in longitudinal compression at ambient temperature, such that any cracks tend not to propagate. The composite membranes are mechanically robust and chemically inert and useful as filters e.g. in the food industry. They may be made by applying a sol or suspension of particles to form a layer on the porous metal support and heating the coated support to partly sinter the particles of the layer.

Abstract: A catalyst device comprises a porous catalytically active inorganic membrane, means for presenting a fluid reactant to a first surface of the membrane and means for recovering a fluid reaction product from the second surface of the membrane. The membrane is preferably an anodic aluminum oxide membrane with a deposit of catalytically active material present within the pores, preferably concentrated in the ends of the pores adjacent the second surface of the membrane.

Abstract: A thin-film solar cell is made up of semiconductor layers formed on an aluminum silicon eutectic alloy substrate. The substrate includes an aluminum oxide insulator containing electrically conducting silicon nucleation sites which is interposed between the electrical contact of the substrate and the adjacent semiconductor. Grain boundaries and voids terminate on the insulator. The solar cell is fabricated by oxidizing the aluminum-silicon substrate to form a layer of aluminum oxide with unactivated silicon site material dispersed therein and activating the silicon nucleation sites during growth of the semiconductor layers.

Abstract: An anodic aluminum oxide film (12) has a system of larger pores (14) extending in from one face (16) and interconnecting with a system of smaller pores (24) extending in from the other face (26). The film is made by anodizing an aluminum metal substrate, then reducing the applied voltage at a rate to permit partial or complete recovery of the oxide film, either continuously or incrementally in small steps down to a level preferably below 3 V, and separating the oxide film from the substrate.