Abstract: A vacuum cleaner including a cleaner head defining a suction chamber and having an agitator arranged to be rotated by an agitator motor, a dirt separator, a vacuum motor arranged to draw air into the suction chamber and then into the dirt separator, and a controller. The controller is configured to monitor the electrical load of the agitator motor, compare the magnitude of the electrical load to a threshold, and selectively adjust the electrical power delivered to the vacuum motor. The controller is configured either to increase the electrical power delivered to the vacuum motor to a predetermined upper power level if the electrical load is greater than the threshold, or to decrease the electrical power delivered to the vacuum motor to a predetermined lower power level if the electrical load is smaller than the threshold.

Abstract: A liquid short-chain polymer of the general formula RaSi(OH)b or (R)aSiHb(OH)c is deposited on a substrate, where a+b=4 or a+b+c=4, respectively, a, b and c are integers, R is a carbon-containing group and a silicon to carbon bond is indicated by Fourier Transfer Infrared analysis. The short-chain polymer is then subjected to further polymerization to form an amorphous structure of the general formula (RxSiOy)n, where x and y are integers, x+y=4, x≠0, n equals 1 to ∞, R is a carbon-containing group and a silicon to carbon bond is indicated by Fourier Transfer Infrared analysis.

Abstract: A process for the scrubbing of species of an element of Group 3, 4 and 5(b) of the Periodic Table from a gas stream. The process comprises contacting the gas stream with an aqueous solution of hydrofluoric acid (HF) or a solution containing the hydrogen fluoride ion HF.sub.2.sup.- and an oxidizing agent.