A New Method for Battery Lifetime Estimation Using Experimental Testbed for Zigbee Wireless Technology

Many Zigbee-based wireless sensor networks have been developed for outdoor applications such as agriculture monitoring. The main attractiveness of Zigbee wireless module is in its potential to set up self-organizing network that requires no network backbone and extremely low cost with low-power wireless networking. Many simulations have been performed for testing the capabilities of wireless communication device and the battery lifetime. However, the results from the simulation do not capture the actual environment effects and the simulators allow users to isolate certain factors by tuning to different parameters. This paper provides experimental results on actual voltage drop using Zigbee protocol devices when communicating temperature, humidity and soil moisture data using a 900mAh battery both in indoor and outdoor environments. It is observed that the wireless nodes are capable of relaying data up to 143 meters on unobstructed line of sights in an outdoor environment with some observation of packet drop. The results differ from previous researches that perform the experiments on shorter range which only covers 50 cm distance between transmitter node and receiver node for 2 bytes of data transfer. The paper proposes a new method for battery lifetime estimation which is derived from number of times data packet can be transmitted. This study also suggests to conduct experiment by including the environmental factors to capture the actual performance of wireless device and the impact to packet drop. The experiment concludes the suitability of Zigbee wireless communication for short-range applications of up to 143 meters which is significantly farther than other reported experiments

HYDROTHERMAL GROWTH AND SQUEEGEE METHOD IN THE FABRICATION OF MIXED-PHASE TiO2 NANOSTRUCTURES

In this work, the modification of TiO2 nanostructures based on its morphology and crystallinity phase were fabricated using a simple method. Hydrothermal growth method was used to synthesize nanorods and nanoflowers, while nanoparticles was applied using squeegee method. The average length and diameter of the as-grown nanorods were 3.5 and 46-215 nm, respectively. Meanwhile, the average total thickness and band gap value of mixed-phase TiO2 nanostructures were 15.98-24.54 nm and 2.84 eV, respectively. Based on its structural and electrical properties, the fabricated film has great potential to be applied as photoanode semiconductor layer for dye-sensitized solar cells application. Key words: TiO2, Nanostructures, Mixed-phase, Hydrothermal, Squeege

THE USE OF TRIPLE-TAILS CUSTOM-MADE SURFACTANT IN THE PRODUCTION OF GRAPHENE OXIDE THIN FILM AS TRANSPARENT CONDUCTIVE ELECTRODE

In this work, graphene oxide (GO) and reduced GO (rGO) thin films were fabricated from GO and rGO using the custom-made and commercial surfactants, which were sodium 1,4-bis (neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate and sodium dodecyl sulphate, respectively. The GO solution was synthesized using electrochemical exfoliation method followed by reduction process utilizing hydrazine hydrate to produce rGO solution. The GO and rGO transfer process were done using spraying deposition method on fluorine-doped tin oxide substrate. The fabricated GO and rGO thin films consists of several layers resulted in high transparency over 85% with maximum transmittance of 93.69%. Based on several characterizations, the fabricated GO and rGO thin films have potential to be applied as transparent conductive electrode.Key words: Custom-made, Surfactant, Electrochemical, Spraying, Electrode. ABSTRAKDalam penelitian ini, film tipis grafin oksida (GO) dan grafin oksida yang direduksi (rGO) difabrikasi dari GO dan rGO menggunakan surfaktan yang dibuat khusus dan surfaktan komersial yaitu secara berurutan adalah sodium 1,4-bis (neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate dan sodium dodecyl sulphate. Larutan GO disintesis menggunakan metode eksfoliasi elektrokimia diikuti dengan proses reduksi menggunakan hidrazin hidrat untuk menghasilkan larutan rGO. Proses transfer GO dan RGO dilakukan dengan menggunakan metode deposisi penyemprotan diatas substrat oksida timah oksida dengan doping florin. Film tipis GO dan rGO yang difabrikasi terdiri dari beberapa lapis dengan transparansi tinggi mencapai 85% dengan transmitansi maksimum sebesar 93,69%. Berdasarkan beberapa karakterisasi, film tipis GO dan rGO ini memiliki potensi untuk diaplikasikan sebagai elektroda konduktif transparan.Kata Kunci: dibuat khusus, surfaktan, elektrokimia, penyemprotan, elektrod

Development of immobilised bioanode for microbial fuel cell

The efficiency of Microbial fuel cell (MFC) performance is based on how well the electron is transferred and finally turned into electrical power in a complete electrical circuit. However, MFC power capacity is still very low compare to similar conceptual fuel cell and one of the major reasons is due to high internal resistance imposed by macro-environment of an MFC. In the present research, the objectives were to develop bio-based anode and its usage in the MFC for power production. The power production was compared using free cells in MFC. The bioanode was developed by mixing cells solution and graphite granules overnight before adding alginate and subjected to homogenisation. The mixture was then immobilised using entrapment method to obtained uniform beads. Initial study was conducted using glucose as fuel and both open circuit voltage (OCV) and closed circuit voltage (CCV) were evaluated using MFC. Results show OCV increased gradually and still increased after 6 h of operation compared to free cells. In CCV profile for free cells show a decrease in voltage generated but then rapidly increased which indicates a 'power-overshoot' phenomenon which was not observe on immobilised based bioanode MFC. The maximum OCV was 2-fold higher for immobilised based bioanode compared to free cells. In conclusion, the immobilised based anode or bio-anode produced was proved viable for MFC application

Enhancing the performance of self-powered ultraviolet photosensor using rapid aqueous chemical-grown aluminum-doped titanium oxide nanorod arrays as electron transport layer

Aluminum (Al)-doped titanium dioxide nanorod arrays (ATNs) were grown on fluorine-doped tin oxide-coated glass at different Al atomic concentrations ranging from 1 at.% to 5 at.% in a Schott bottle through single-step aqueous chemical growth for self-powered photoelectrochemical cell-type ultraviolet (UV) photosensor applications. X-ray diffraction patterns showed that the grown ATNs exhibited a crystalline rutile structure. The ATNs showed smaller crystallite size and average nanorod diameter and length compared with the undoped sample. The photocurrent measured from the fabricated UV photosensors improved to some extent with increasing Al-dopant concentration. Samples with 2 at.% Al showed the maximum photocurrent of 108.87 μA/cm2 at 0 V bias under UV irradiation (365 nm, 750 μW/cm2). The results show that high-performance UV photosensors can be fabricated and enhanced using ATNs easily prepared in a glass container

Optimisation of silicone-based dielectric elastomer transducers by means of block copolymers – synthesis and compounding

Emerging artificial muscle technology has developed from metal-based robotics to softtype robotics made from soft matter. Research into artificial muscle technology based on soft matter has been conducted mainly in order to mimic soft and robust human muscle. In this regard, dielectric elastomers have been studied. Their actuation occurs when Maxwell stress exceeds elastic stress in the presence of an electrical field, resulting in contraction in thickness and planar expansion in the area. As well as an actuator, dielectric elastomers can be used as generators and sensors. As a dielectric elastomer, silicones have been used extensively in many applications, due to favourable properties such as thermal stability, non-conductivity, high gas permeability and low toxicity. However, silicones have a low dielectric constant and thereby low energy density. In order to enhance actuation performance, it is the aim of this research to develop silicone elastomers with a high dielectric constant and high electrical breakdown strength, as well as a low Young’s modulus. In this Ph.D. thesis, two methods were developed to enhance silicone properties such as the dielectric constant and electrical breakdown strength. The first method was devised to enhance the dielectric constant of silicone elastomers through the use of a polydimethylsiloxane-polyethyleneglycol (PDMS-PEG) copolymer, in order to obtain an elastomer with high electrical energy. PDMS-PEG copolymers were synthesised and blended in commercial silicone and subsequently cross-linked. The relative permittivity of cross-linked silicone with 5 wt% of PDMS-PEG copolymers increased by nearly 50%, without compromising dielectric loss and mechanical properties, compared to the commercial silicone elastomer. The second investigated method involved enhancing the electrical breakdown strength of silicone by using an aromatic voltage stabiliser. Here, polyphenylmethylsiloxane (PPMS), which contained aromatic voltage stabilisers, was bonded covalently to PDMS through a hydrosilylation reaction obtaining PDMS-PPMS copolymers. The synthesised copolymers were subsequently cross-linked with a vinyl cross-linker. The obtained cross-linked PDMS-PPMS copolymers were inherently soft and robust with increased electrical breakdown strength (21%) compared to the reference elastomer without an aromatic voltage stabiliser. The conducting polymer was developed through the use of a multi-walled carbon nanotube (MWCNT) in a PDMS-PEG matrix as a compliant electrode of dielectric elastomers. The conductive PDMS-PEG copolymer was incorporated with surface-treated MWCNT, in order to obtain highly conductive elastomer. The prepared sample with 4 parts per hundred rubber (phr) MWCNT was soft and the resulting conductivity of the cross-linked PDMS-PEG copolymer with the addition of MWCNT was high, at 10-2 S cm-1, nearly equivalent to a commonly used commercial conducting polymer. In this thesis, the elastomer and electrode system is referred to as a ‘dielectrielastome

Digital aerial imagery of unmanned aerial vehicle for various applications

Digital aerial imagery (DAI) can be acquired using digital mapping camera attached to light aircraft. The DAI is used for the production of topographic and thematic map. The cost of acquiring DAI is very expensive and suitable for large area coverage. The acquisition of DAI is not economical and suitable for small area coverage. Therefore an alternative method should be used to fulfill this need. There are two alternative methods that can be used for acquisition of DAI which include using a small format digital camera attached to light aircraft and using a small format attached to an unmanned aerial vehicle (UAV). UAV system has been reported used in various and diversified applications such as mapping applications (eg. map revision, landslide, coastal erosion, archaeology, forestry), industrial application (eg. engineering, crash accident), Geographic Information System (GIS) applications and others. In this study, micro unmanned aerial vehicle (UAV) systems which comprise of fixed wing UAV flying and rotary UAV are attached with small format high resolution digital camera to acquire DAI for the purpose of mapping at the flying height of 300m at 100m respectively. The micro UAVs were flown autonomously (i.e automatically) and a series of DAIs of a slope using fixed wing UAV and a stream using rotary UAV were acquired rapidly within short period. Ground control point (GCP) and check point (CP) were established using the Global Positioning System and conventional Total Station techniques around the study area for the slope and stream respectively for the purpose of digital image processing and accuracy assessment. The DAIs were processed to produce photogrammetric output such as digital elevation model (DEM) and orthophoto. All these photogrammetric products were successfully produced and assessed. The achievable accuracy is less than ±1m for slope mapping and ±0.280m for stream mapping. In this study, it is proven that the micro UAV system can be used for mapping which cover small area. As conclusion, micro UAV is suitable for mapping small area, rapid data acquisition, accurate, low cost and can be employed for various applications