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Open rotors are an engine technology that could bring a step change in propulsive efficiency for the next generation of aircraft. As such, there is a large research effort that aims to accurately predict the noise radiated by open rotors. This thesis focuses on the noise radiated by an installed open rotor. In this configuration one of the major noise sources could be the ingestion of a turbulent boundary layer that has developed on the fuselage of the aircraft. This thesis presents an analytical model that predicts this noise source. The analytical model is based on the simplified rotor noise model of Amiet with blade-to-blade correlation modelled. The model is extended in three ways to include the boundary layer ingestion noise source. The first extension is to include a numerical switch to model the partial loading of a rotor ingesting a boundary-layer. The second extension is to include wall-effects using the method of images. The assumptions that are made in the method of images are tested by examining the simpler case of a two-dimensional aerofoil ingesting turbulence in proximity to a hard-wall. This is done by extending Amiet's two dimensional leading-edge noise model and comparing the predictions from this model to two Computational Aeroacoustic (CAA) simulations. The first CAA simulation uses the method of images to model the wall and the second uses a physically representative hard-wall boundary condition to model the wall. By comparing the differences between the analytical predictions and the CAA simulations, it is shown that the method of images accurately predicts wall-effects except for a small range of observers that are in the shadow-zone of the aerofoil. The method of images is then implemented in the rotor noise model to predict wall-effects for a rotor. Finally, an axisymmetric anisotropic turbulence model is used to approximate boundary layer turbulence. The extended rotor noise model is validated by comparing it to experimental measurements and to a time-domain rotor noise model that does not model boundary layer turbulence.

For sensors and actuators that use microdischarges, microfabrication technology provides both portability and ease of integration into microsystems. This thesis investigates two types of microfabricated devices: sputter ion pumps (SIP) to control on-chip vacuum, and miniature radiation detectors for sensing beta particles, gamma rays or neutrons. The SIP utilizes lithographically micromachined Penning cell array to ignite a plasma at pressures as low as 1.5 µTorr. The system pressure is reduced from 1 Torr to 2000 V for commercial devices. The resulting power consumption is 100-250 mW. The overall pump volume is 0.2 cm3. A microfabricated neutron detector, operating in the Geiger Muller regime, utilizes electrodes that are lithographically micromachined from 50-µm thick stainless steel #304 foil. The cathode is coated with 2.9-µm thick layer of Gd on one side to convert thermal neutrons into fast electrons and gamma rays, which are then detected by ionization of the fill gas (Ar). Three electrodes are stacked in a cathode-anode-cathode arrangement, separated by 70-µm thick polyamide spacers, and assembled within a commercial TO-5 package. For a 90 µCi 252Cf neutron source, placed at a distance of 10 cm from the detector, the total neutron count rate with an applied voltage of 285 V is typically 8.7 counts per minute (cpm). Detector dead time is measured as 5.3 ms. The device is operated at lower voltages with a reduced volume and can detect beta particles, gamma rays and neutrons, when compared to commercial devices which operate at >900 V, have a higher detector volume (>100 mm3) and can only detect a subset of the listed radiation. Finally, this thesis describes a new architecture for microdischarge based radiation detectors intended to enhance stability, improve sensitivity and reduce dead time. The device stability can be improved through use of an asymmetric electric field between the anode and cathode. Detector sensitivity can be improved through use of stacked cathodes as it increases radiation interaction probability. The device dead time can be improved by having multiple detectors operate in parallel.

Thesis presents a two-way wireless communication link that is capable of transferring data from a remote module to a PC/Laptop. The primary need of the wireless link is to periodically monitor the output from electrochemical microelectrodes deployed in the field. The system has feature of programmability for the sensors with configuration bits that are communicated from the base station. The uniqueness in the design is a bidirectional communication interface which allows communication to be initiated by the remote side while allowing the base station side to determine the nature of the communication packet. The system uses data transceivers, in the Industrial, Scientific and Medical (ISM) Radio Bands or in the 902–928 MHz (Centre frequency 915 MHz) band, and employs two way communication protocols depending on the required data collection rate and accuracy. The system design presents the system architecture, the interface logic on the sensor and user side to transmit/receive the data and the programmability interface of the sensor data from the PC/Laptop. The base station (PC/Laptop) manages the transceivers by issuing configuration, data acquisition, and transmission commands using wireless techniques. For data acquisition a USB interface has been designed at the base station to transfer data from transceiver to Laptop/PDA/PC.