Abstract: A luminometer apparatus has a light-tight box (12) into which a cuvette (2) containing a sample and a reagent are located for producing a phosphorescent reaction. The phosphorescent reaction is detected by a photodetector (PD) and a shutter (3) is interposed between the cuvette and the shutter. Output signals from the photodetector are applied to a circuit arrangement (FIG. 4) which detects the phosphorescent reaction at predetermined intervals and by subtracting the successive values of light from one another so a measured peak value of light intensity is determined. The shutter is closed and the dark current signal of the photodetector is determined and subtracted from the measured peak value. A true peak intensity of the emitted light is thus derived and the concentration of the material being assayed is calculated by raising the peak intensity to the power n where n has a value between 0 and 9 predeterminedly derived for the sample.

Abstract: A single-crystal ingot I of boron-doped silicon is electron-beam heated in ionized hydrogen. Using an electrode E to apply an electric field from the ingot I towards a heated substrate S, which is r.f. biassed, an amorphous boron-doped silicon film deposits on the substrate S.Intrinsic and n-type material can also be produced.

Abstract: In a hot water process for extracting bitumen from tar sands comprising forming a mixture of tar sands and water, settling the mixture in a primary extraction zone to form an upper bitumen froth layer, a middlings layer and a sand tailings layer, passing a part of the middlings layer to an air scavenger zone to recover additional bitumen therefrom, the improvement which comprises adding the aerated bitumen-depleted aerated middlings material from the air scavenger zone to the mixture of tar sands and water before the settling step.

Abstract: In a hot water process for extracting bitumen from tar sands comprising forming a mixture of tar sands and water, settling the mixture in a primary extraction zone to form an upper bitumen froth layer, a middlings layer, and a sand tailings layer, passing a part of the middlings layer to an air scavenger zone to recover additional bitumen therefrom, the improvement which comprises aerating the mixture of tar sands and water before separating bitumen froth from the mixture in a gravity settling zone. This aeration can be accomplished by adding an aerated recycle middlings stream to the tar sands water-mixture prior to the settling step.

Abstract: A method for improving recovery in a hot water process for extracting bitumen from tar sands comprising adding bitumen-depleted middlings recovered from a scavenger zone to the sand layer in a primary extraction vessel at a point below the surface of the sand.