68 research outputs found

    Implementation of Local Transport Protocol Library (LTPlib) into Real-time Operating System (RTOS)

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    Healthcare is getting more expensive overtime. Personal telehealth systems, including remote patient monitoring and management, can facilitate caregiver to effectively deliver high-quality healthcare service at lower cost. The recent developments in information and communication technologies have increased the degree of connectivity between people using smart devices. To further enhance these developments, implementation of the Local Transport Protocol library is ported to a micro real-time operating system to achieve a low cost yet highly efficient embedded system.The selected hardware and software provide easy interface for data transfer from a monitoring and measuring device to remote locations. Targeting the Continua Health Alliance compliancy as the future task of this research and development work can be a significant contribution to the future of healthcare monitoring system

    Design and fabrication of PCR chip with integrated dielectrophoretic based sample pretreatment

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    Development of effective thermal management strategies for LED luminaires

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    The efficacy, reliability and versatility of the light emitting diode (LED) can outcompete most established light source technologies. However, they are particularly sensitive to high temperatures, which compromises their efficacy and reliability, undermining some of the technology s key benefits. Consequently, effective thermal management is essential to exploit the technology to its full potential. Thermal management is a well-established subject but its application in the relatively new LED lighting industry, with its specific constraints, is currently poorly defined. The question this thesis aims to answer is how can LED thermal management be achieved most effectively? This thesis starts with a review of the current state of the art, relevant thermal management technologies and market trends. This establishes current and future thermal management constraints in a commercial context. Methods to test and evaluate the thermal management performance of a luminaire system follow. The defined test methods, simulation benchmarks and operational constraints provide the foundation to develop effective thermal management strategies. Finally this work explores how the findings can be implemented in the development and comparison of multiple thermal management designs. These are optimised to assess the potential performance enhancement available when applied to a typical commercial system. The outcomes of this research showed that thermal management of LEDs can be expected to remain a key requirement but there are hints it is becoming less critical. The impacts of some common operating environments were studied, but appeared to have no significant effect on the thermal behaviour of a typical system. There are some active thermal management devices that warrant further attention, but passive systems are inherently well suited to LED luminaires and are readily adopted so were selected as the focus of this research. Using the techniques discussed in this thesis the performance of a commercially available component was evaluated. By optimising its geometry, a 5 % decrease in absolute thermal resistance or a 20 % increase in average heat transfer coefficient and 10 % reduction in heatsink mass can potentially be achieved . While greater lifecycle energy consumption savings were offered by minimising heatsink thermal resistance the most effective design was considered to be one optimised for maximum average heat transfer coefficient. Some more radical concepts were also considered. While these demonstrate the feasibility of passively manipulating fluid flow they had a detrimental impact on performance. Further analysis would be needed to conclusively dismiss these concepts but this work indicates there is very little potential in pursuing them further

    Cyber-Human Systems, Space Technologies, and Threats

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    CYBER-HUMAN SYSTEMS, SPACE TECHNOLOGIES, AND THREATS is our eighth textbook in a series covering the world of UASs / CUAS/ UUVs / SPACE. Other textbooks in our series are Space Systems Emerging Technologies and Operations; Drone Delivery of CBNRECy – DEW Weapons: Emerging Threats of Mini-Weapons of Mass Destruction and Disruption (WMDD); Disruptive Technologies with applications in Airline, Marine, Defense Industries; Unmanned Vehicle Systems & Operations On Air, Sea, Land; Counter Unmanned Aircraft Systems Technologies and Operations; Unmanned Aircraft Systems in the Cyber Domain: Protecting USA’s Advanced Air Assets, 2nd edition; and Unmanned Aircraft Systems (UAS) in the Cyber Domain Protecting USA’s Advanced Air Assets, 1st edition. Our previous seven titles have received considerable global recognition in the field. (Nichols & Carter, 2022) (Nichols, et al., 2021) (Nichols R. K., et al., 2020) (Nichols R. , et al., 2020) (Nichols R. , et al., 2019) (Nichols R. K., 2018) (Nichols R. K., et al., 2022)https://newprairiepress.org/ebooks/1052/thumbnail.jp

    An investigative study of Manganese-based Antiperovskite structures as a thin film resistive material system

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    Novel manganese (Mn) based antiperovskite material systems have been reported to have Temperature Coefficient of Resistance (TCR) in the range of +0.09 to +46 ppm/˚C. Such extremely low values of TCR make these materials an ideal choice to replace existing thin film resistor systems like NiCr and TaN, which are reaching their current limit at ±5 ppm/˚C. These ultra-precise passive components find use in applications such as medical diagnostics, industrial automation and military systems, where they must maintain a stable resistance value across an extreme temperature range of -55 to +155 ˚C throughout their lifetime. Based on previous literature, Mn based antiperovskites: Mn3AgN, Mn3CuN and Mn3Ag(x)Cu(1-X)N were selected to be sputter deposited as thin films on alumina and glass substrates using industrial standard fabrication processes to enable future scale up of the developed material. The experiments within this project focus on fine-tuning key deposition parameters of nitrogen flow rate, temperature and pressure to investigate their effect on electrical properties of TCR and stability of Mn based antiperovskite thin films. The as-grown values of electrical properties are stabilised by finely tuning heat treatment temperature, time and environment. To assess the scope of improvement in electrical properties, Ag was partially substituted by Cu in the Mn3Ag(X)Cu(1-X)N structure. Sputter deposition parameters, heat treatment parameters and chemical composition were tuned to target resistive films with TCR values lower than ±5ppm/ºC and stability values closer to industry standard of 0.05%. The lowest TCR value achieved for binary Mn3CuN films was +14.25ppm/˚C and this was improved to -4.66ppm/˚C by partially substituting Cu with Ag in the films to a composition of Mn3Ag(0.4)Cu(0.6)N. The best stability value of 0.57% was achieved for Mn3CuN and this value deteriorated with increasing content of Ag in the film. The Mn3CuN films also performed extremely well through the industrial fabrication stages, yielding a stable variation in TCR value of <±3ppm/˚C. This research is an important step in establishing the low TCR nature of Mn based antiperovskite materials suitable for industrial scale fabrication of thin film resistors

    A novel low-temperature growth method of silicon structures and application in flash memory.

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    Flash memories are solid-state non-volatile memories. They play a vital role especially in information storage in a wide range of consumer electronic devices and applications including smart phones, digital cameras, laptop computers, and satellite navigators. The demand for high density flash has surged as a result of the proliferation of these consumer electronic portable gadgets and the more features they offer – wireless internet, touch screen, video capabilities. The increase in the density of flash memory devices over the years has come as a result of continuous memory cell-size reduction. This size scaling is however approaching a dead end and it is widely agreed that further reduction beyond the 20 nm technological node is going to be very difficult, as it would result to challenges such as cross-talk or cell-to-cell interference, a high statistical variation in the number of stored electrons in the floating gate and high leakage currents due to thinner tunnel oxides. Because of these challenges a wide range of solutions in form of materials and device architectures are being investigated. Among them is three-dimensional (3-D) flash, which is widely acclaimed as the ideal solution, as they promise the integration of long-time retention and ultra-high density cells without compromising device reliability. However, current high temperature (>600 °C) growth techniques of the Polycrystalline silicon floating gate material are incompatible with 3-D flash memory; with vertically stacked memory layers, which require process temperatures to be ≤ 400 °C. There already exist some low temperature techniques for producing polycrystalline silicon such as laser annealing, solid-phase crystallization of amorphous silicon and metal-induced crystallization. However, these have some short-comings which make them not suitable for use in 3-D flash memory, e.g. the high furnace annealing temperatures (700 °C) in solid-phase crystallization of amorphous silicon which could potentially damage underlying memory layers in 3-D flash, and the metal contaminants in metal-induced crystallization which is a potential source of high leakage currents. There is therefore a need for alternative low temperature techniques that would be most suitable for flash memory purposes. With reference to the above, the main objective of this research was to develop a novel low temperature method for growing silicon structures at ≤ 400 °C. This thesis thus describes the development of a low-temperature method for polycrystalline silicon growth and the application of the technique in a capacitor-like flash memory device. It has been demonstrated that silicon structures with polycrystalline silicon-like properties can be grown at ≤ 400 °C in a 13.56 MHz radio frequency (RF) plasma-enhanced chemical vapour deposition (PECVD) reactor with the aid of Nickel Formate Dihydrate (NFD). It is also shown that the NFD coated on the substrates, thermally decomposes in-situ during the deposition process forming Ni particles that act as nucleation and growth sites of polycrystalline silicon. Silicon films grown by this technique and without annealing, have exhibited optical band gaps of ~ 1.2 eV compared to 1.78 eV for films grown under identical conditions but without the substrate being coated. These values were determined from UV-Vis spectroscopy and Tauc plots. These optical band gaps correspond to polycrystalline silicon and amorphous silicon respectively, meaning that the films grown on NFD-coated substrates are polycrystalline silicon while those grown on uncoated substrates remain amorphous. Moreover, this novel technique has been used to fabricate a capacitor-like flash memory that has exhibited hysteresis width corresponding to charge storage density in the order of 1012 cm-2 with a retention time well above 20 days for a device with silicon films grown at 300 °C. Films grown on uncoated films have not exhibit any significant hysteresis, and thus no flash memory-like behaviour. Given that all process temperatures throughout the fabrication of the devices are less than 400 °C and that no annealing of any sort was done on the material and devices, this growth method is thermal budget efficient and meets the crucial process temperature requirements of 3-D flash memory. Furthermore, the technique is glass compatible, which could prove a major step towards the acquisition of flash memory-integrated systems on glass, as well as other applications requiring low temperature polycrystalline silicon

    Faculty Publications & Presentations, 2001-2002

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    Sustainability through subsistence: the case for de-urbanization in Malaysia

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    Industrialization was the catalyst for the growth of cities in Southeast Asia, in particular Malaysia. However, in many cities industrialization has peaked and is now declining. This raises the issue of increased urban poverty as a significant problem facing these cities in the 21st century. Evidence from other developing countries is that faced with the choice of urban poverty or rural subsistence, there appears to be a trend towards de-urbanization. As Malaysia is unique in imposing laws that protect rural land ownership, this study investigates the capacity of the available land to absorb migrants from the city and seeks to identify whether the returning migrants have the capabilities required to maintain a subsistence lifestyle. This paper presents a case study analyzing the trends of urban to rural migration in Malaysia. An audit of land capacity was carried out in a typical kampong and an investigation of the capability of migrants has been done in both urban and rural areas. In conclusion, this study has found that the land abandoned by the rural-urban migration of the 1970s is available and remains accessible for future use. The findings also identified several examples of returnees who have shown that they have adapted well to a rural lifestyle. The results indicate that there is evidence that de-urbanization can result in a sustainable lifestyle through subsistence living in Malaysia

    Power from the people: the empowerment of distributed generation of solar electricity for rural communities in Malaysia

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    This paper describes the decreasing energy security in Malaysia and the likely impact on maintaining power supplies to low income groups. The most vulnerable group is the low-income people in the rural areas, who have limited access to generate their own power supplies. The paper reviews the potential of distributed generation (DG) using photovoltaics as a means of mitigating this problem. Examples from other countries are reviewed and alternative methods of funding PV installations are discussed. Strategies such as community-based approach and innovative financing scheme will be introduced and discussed. The main objective is to utilize solar energy as the main energy resources for generating electricity and places rural people as the main stakeholder to deploy the strategic model. This model is also ideal to be integrated with the distributed generation (DG) system as one of the key components in developing a suitable energy policy that can helps to sustain the energy development of rural community in the future. The paper concludes that distributed generation (DG) is feasible and that innovative funding schemes are required based on local knowledge
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