A. I. Al-Shamma'a

Propagation of electromagnetic waves at MHz frequencies through seawater

The nature of the ocean environment and its vast size has necessitated the development of sophisticated equipment and techniques for various underwater applications including diver-to-diver communications, ROV/AUV docking, communications and oil and gas explorations. To facilitate scientific exploration a wide variety of systems and vehicles have been developed to operate within the shallow continental shelf region or in deep oceans. For successful underwater electromagnetic (EM) wave operation, knowledge is required of the wave transmission properties of seawater over all distances both short and long. This information is required for such activities such as: sensor systems, imaging, position fixing, measurement of speed, obstacle detection and avoidance, guidance, communication of data/voice and remote control. This paper presents a new approach of EM wave propagation through seawater. The experimental results conducted in the laboratory and the real environment of seawater is presented.

Experimental Investigations of Electromagnetic Wave Propagation in Seawater

It is often preferable to avoid using divers to undertake sub-sea activities, the alternatives being autonomous or remotely operated robotic vehicles and manipulators. This will only be achievable if robust communications can be established through seawater. Presently for such sub-sea activities it is necessary to use acoustic modems, which are only capable of operating with data rates of up to 50kbs-1. Optical sensors can also be used but these rely on clear water and in many sea conditions propagation beyond 10m is not possible. This paper presents new experimental results for electromagnetic wave propagation through seawater at MHz frequencies. These frequencies would enable the use of high speed data rates, suitable for a wide range of sub-sea activities

RF sensor for multiphase flow measurement through an oil pipeline

We have developed, in conjunction with Solartron ISA, an electromagnetic cavity resonator based sensor for multiphase flow measurement through an oil pipeline. This sensor is non-intrusive and transmits low power (10 mW) radio frequencies (RF) in the range of 100–350 MHz and detects the pipeline contents using resonant peaks captured instantaneously. The multiple resonances from each captured RF spectrum are analysed to determine the phase fractions in the pipeline. An industrial version of the sensor for a 102 mm (4 inch) diameter pipe has been constructed and results from this sensor are compared to those given by simulations performed using the electromagnetic high frequency structure simulator software package HFSS.

Online vehicle and atmospheric pollution monitoring using GIS and wireless sensor networks

A Geographical Information System (GIS) is a computer system designed to integrate, store, edit, analyse, share and display geographically referenced data. A wireless sensor network (WSN) is a wireless network of spatially distributed autonomous devices using sensors to monitor physical or environmental conditions. This paper presents the integration of these two technologies to create a system able to detect measure and transmit information regarding the presence and quantities of internal combustion derived pollution and the geographical location in real time with the aim of creating pollution maps in urban environments.

A review of optical fibre radiation dosimeters

Purpose – The purpose of this paper is to provide a detailed review of radiation dosimetry techniques based on optical fibre dosimeters. It presents a comprehensive bibliography of the current research activities in the area.Design/methodology/approach – A range of published work on optical fibre radiation dosimeters are presented, with the merits and limitations discussed. Each radiation dosimetry technique is discussed in turn, providing examples of dosimeters using such techniques reviewed. The main focus is on gamma radiation although other radiation dosimeters are considered.Findings – This paper provides information on the wide range of research activity into radiation dosimeters. The dose ranges of these dosimeters are presented, along with the advantages and disadvantages of different dosimetry techniques.Originality/value – A comprehensive review of published research in the area of solid radiation dosimetry is presented in this paper. It provides an individual with a review of the various techni...

Design and construction of a 2.45 GHz waveguide-based microwave plasma jet at atmospheric pressure for material processing

We have designed a low-cost and reliable 2.45 GHz waveguide-based applicator to generate a microwave plasma jet (MPJ) at atmospheric pressure. The MPJ system consists of a 1-6 kW magnetron power supply, a circulator, a water-cooled matched load and the applicator. The applicator includes a tuning section, which is required to reduce the reflected power, and the nozzle section. The plasma is formed by the interaction of the high electrical field, generated by the microwave power, between the waveguide aperture and the gas nozzle. A variety of gases have been used to produce the plasma including argon, helium and nitrogen. A 2 kW, 2.45 GHz MPJ, constructed using a rectangular waveguide WG9A (WR340), has been investigated. An MPJ has been used for material processing applications including cutting, welding, glass vitrification and quartz/ceramic processing. This paper discusses the design parameters and the potential of the MPJ for industrial applications and how the jet can be tailored to suit different tasks, by adjusting the various parameters such as the type of gas, the flow rate, the input power and the nozzle design.

Microwave sensors for the non-invasive monitoring of industrial and medical applications

Purpose – This paper aims to discuss the general principles behind the microwave sensing and demonstrates the potential of cavity microwave resonator device in real-time monitoring for: environmental monitoring with the focus on wastewater pollution, a system for oil/gas/water content evaluation in a dynamic pipeline, a system for real-time determination of bacteria concentration and a method for non-invasive glucose determination. Design/methodology/approach – Microwave sensing is a rapidly developing technology which has been successfully used for various industrial applications including water level measurements, material moisture content, in construction industry for non-invasive evaluation of structures and even in the healthcare industry for non-invasive real-time monitoring of glucose in diabetic patients. Novel microwave cavities designed and tested for specific applications are presented. Findings – The paper provides experimental results of testing the novel microwave sensing systems in a range ...

Keynote speakers: Wireless power transfer: From long-distance transmission to short-range charging

Since Nikola Tesla proposed the Wardenclyfee Tower in 1889 for the wireless power transmission to date, it has been over a century. The idea was later picked up and implemented continuously in the last half a century. Recently in 2007, MIT research group picked up the old concept and implemented for potential applications into telecommunications. This talk will address briefly the state of-the-art research and development progresses in the wireless power transmission technology and also potential applications. The talk is categorized into two aspects, that is, (a) the long-distance and high-power wireless energy transmission and (b) the short-range and low-power wireless energy transmission. For the long-distance high-power transmission, the talk will cover atmospheric effects, high-power microwave generation, transmitting antennas, EMC/EMI effects on radio frequency wireless system, rectennas, and biological effects on human being and animals. For the short-range wireless power transmission, the review will touch inductive couple effects and their applications onto power-grid systems, wireless power charging systems, mine-tunnel power charge system, and medical applications. The talk will, of course, discuss on advantages and short-comings of these proposals.

Low-pressure microwave plasma ultraviolet lamp for water purification and ozone applications

Low-pressure mercury lamps are commonly used for germicidal applications. The germicidal effect is due to the emission of light at 254 nm, which leads to the destruction of the most waterborne bacteria and viruses. The microwave plasma ultraviolet (UV) lamp (MPUVL) is a new technology for generating a high-intensity UV light and that can be also controlled to operate at 185 nm; irradiation is in air at this wavelength produces ozone. The microwave power is injected into a resonant cavity and the surface wave excitation takes place within the cavity through that part of the discharge tube (fused silica) protruding inside it. The MPUVL has many advantages over conventional lamps, which are limited to an output power in the region of 30 W m-1, while MPUVL can deliver any amount of power per unit length and the tube can be of any shape, length or diameter. This paper describes the design of the MPUVL and compares its efficiency with that of conventional lamps through spectral analysis. Other results, which include the effects of temperature and different power inputs, are also discussed.

Glucose monitoring using electromagnetic waves and microsensor with interdigitated electrodes

A microscale glucose sensor for biomedical applications was fabricated utilizing the enzyme glucose oxidase and the polymer poly(o-phenylenediamine). A solution containing the enzyme immobilized in the polymer was deposited on interdigitated microelectrodes to form sensor arrays. This was achieved using novel nanopatterning technology offered by BioForce NanoeNabler™. Samples containing different concentrations of glucose were applied to the sensor while the system was being monitored for variances in either current or conductance. The resulting changes in the electrical characteristics of the sensor monitored in real time were found to be proportional to the different concentrations of glucose applied. It is strongly believed that the size reduction of the sensor to a few microns described in this paper creates new opportunities in the areas of chemical and biological sensor development.