Human respiration rate estimation using ultra-wideband distributed cognitive radar system

It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare, rescue, and security applications. In this paper, we first present a multi-ray propagation model for UWB signal, which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces. A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment. This model enables replication of time-varying multipath profiles due to the displacement of a human chest. Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate. The analytical framework can serve as a basis in the planning and evaluation of future measurement programs. We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture

Laser Doppler velocimetry measurements of particle velocity profiles in gas-solid two-phase flows

The measurement of particle velocities in two-phase gas-solid systems has a wide application in flow monitoring in process plant, where two-phase gas-solids systems are frequently employed in the form of pneumatic conveyors and solid fuel injection systems. Such measurements have proved to be difficult to make reliably in industrial environments. This paper details particle velocity measurements made in a two phase gas-solid now utilising a laser Doppler velocimetry system. Tests were carried out using both wheat flour and pulverised coal as the solids phase, with air being used as the gaseous phase throughout. A pipeline of circular section, having a diameter of 53 mm was used for the test work, with air velocities ranging from 25 to 45 m/s and suspension densities ranging from 0.001 kg to 1 kg of solids per cubic meter of air. Details of both the test equipment used, and the results of the measurements are presented.