Abstract: An optical sensor for measuring physical properties of a strand includes a light source, and a pixel array having a plurality of pixels facing the light source. The array and light source define an area in which the strand is positioned so that an image of the strand is captured on the array by generating an output value at each of the pixels relative to an intensity of the light received at each of the pixels from the light source. A digital signal processor receives and processes the output value for each of the pixels to extract a particular physical property of the strand. The output value of each pixel can be an analog value, and the signal processor can digitize the analog value to generate a digitized value for each pixel.

Abstract: A gas turbine (12) capable of combusting a low quality gaseous fuel having a ratio of flammability limits less than 2, or a heat value below 100 BTU/SCF. A high quality fuel is burned simultaneously with the low quality fuel to eliminate instability in the combustion flame. A sensor (46) is used to monitor at least one parameter of the flame indicative of instability. A controller (50) having the sensor signal (48) as input is programmed to control the relative flow rates of the low quality and high quality fuels. When instability is detected, the flow rate of high quality fuel is automatically increased in relation to the flow rate of low quality fuel to restore stability.

Abstract: A gas turbine (12) capable of combusting a low quality gaseous fuel having a ratio of flammability limits less than 2, or a heat value below 100 BTU/SCF. A high quality fuel is burned simultaneously with the low quality fuel to eliminate instability in the combustion flame. A sensor (46) is used to monitor at least one parameter of the flame indicative of instability. A controller (50) having the sensor signal (48) as input is programmed to control the relative flow rates of the low quality and high quality fuels. When instability is detected, the flow rate of high quality fuel is automatically increased in relation to the flow rate of low quality fuel to restore stability.