Abstract: A non-intrusive mass flow measuring apparatus includes a sensor unit and a processor unit. The sensor unit includes a sensor conduit, a heating element, and three separate temperature sensor elements. The three temperature sensor elements are spaced out along the length of the sensor conduit from the heating element. The middle, compensating temperature sensor element, enables the coefficient of conductive heat transfer along the conduit to be decoupled from the coefficient of convective heat transfer from the fluid, from which mass flow may be derived. A processor uses the temperatures sensed by the three sensors to determine a normalized temperature parameter related to the coefficient of convective heat transfer, and then utilizes temperature data and the normalized temperature parameter in a preferably empirically determined relationship to determine a mass flow value.

Abstract: A beta radiation sensor and an X-ray radiation sensor are used to monitor the specific weights of both components of a two-component web, in particular, a web of magnetic recording material, by using the beta radiation sensor to measure the combined specific weight of the material. The measurement by the X-ray sensor permits such combined specific weight to be apportioned between the two components of the web. Cross talk between the two sensors arising from bremstrahlung produced by the beta radiation sensor is suppressed by softening the beta radiation beam with films of polyester, by shielding the housing in which the detectors of the two sensors are disposed with a sheet of phenolic, and by stopping down the aperture through the sheet of phenolic through which X-ray radiation enters the detector housing.

Abstract: A low-pass filter passes a spectrum of electrical signals which are utilized to establish a threshold level with which electrical signals having frequencies in a relatively higher range are compared to determine if a warning sound is present in the sounds in the vicinity of a receiver unit for receiving the ambient sound. If the rectified magnitude of the signals having the higher frequencies exceeds the rectified and variably adjusted magnitudes of the signals having lower frequencies, a visual indication is given to communicate the existence of a warning sound in the ambient sounds.

Abstract: A sound level indicator apparatus includes a signal processing element which detects and processes sound pressure waves into quantifiable electrical signals. The indicator also includes an adjustment member which adjusts the quantifiable signals to compensate for intrinsic electrical variations in the processing element. Further included is a monitoring member which detects when the received sound is below a predetermined level. The indicator still further includes an indicator element which displays the quantified quantifiable signals and the low level monitor detection signal. The sound level indicator is operatively combined with a digital watch integrated circuit for containment in a case which is wearable on one's wrist.