Mahyuddin Arsat

Three dimensions of characterizing courses for sustainability in engineering education: Models, approaches and orientations

Worldwide universities are changing their curriculum in response to the Barcelona Declaration. The adaptations include the integration of sustainability courses in engineering education. The various courses have been constructed with different kind of earning objectives and different interpretations of the stainability concept. The paper introduces three dimensions of characterizing sustainability courses in engineering education; models, approaches and orientations. The paper reviews 30 articles and presents examples of sustain ability courses that have been characterized based on the three dimensions. The conclusion is that the three dimensions of characterization can provide concrete perspectives on constructing and designing of sustainability course in engineering education.

Performance Analysis of Sub Carrier Multiplexed System for Radio over Fiber Technology

Radio over fiber (RoF) technology or micro cellular over fiber is proposed solution for reducing cost and providing high reliable communication services. The system is a technique that modulates microwave signals on optical domain. In this hybrid technology, which synergies of the two communication domains, optical and radio, the technology is proposed for future generation of wireless radio communication system to serve high quality broadband service in highly dense and mobile users. In this paper, we proposed subcarrier multiplexed (SCM) technique for data transmission for the RoF. The design and performance analysis of the system in term of signal power, Bit Error Rate (BER), carrier to noise ratio (CNR) and eye diagram will be presented. This performance analysis was focus on a link between two stations; a transmitter and receiver. The designed SCM-RoF system was employing PSK as the RF modulation scheme which presents four input signals at the transmitter. At the optical domain, the CW Laser diode was used as the optical source, while Mach Zender as the optical modulator and RF modulated optical signal will be detected by a photodiode. Whereby, the transmission link employing step index single mode fiber up to 150 km communication distance. The result is very convincing inline with theory for practical demonstration of the SCM-RoF system.

Polyvinylpyrrolidone/Multiwall Carbon Nanotube Composite Based 36° YX LiTaO3 Surface Acoustic Wave For Hydrogen Gas Sensing Applications

Poly‐vinyl‐pyrrolidone (PVP) /Multiwall Carbon Nanotubes (MWNTs) based Surface Acoustic Wave (SAW) sensors are fabricated and characterized, and their performances towards hydrogen gas are investigated. The PVP/MWNTs fibers composite are prepared by electrospinning of the composite aqueous solution deposited directly onto the active area of SAW transducers. Via scanning electron microscopy (SEM), the morphology of the deposited nanostructure material is observed. From the dynamic response, frequency shifts of 530 Hz (1% H2) and 11.322 kHz (0.25% H2) are recorded for the sensors contain of 1.525 g and 1.025 g PVP concentrations, respectively.

Polyvinylpyrrolidone/multiwall carbon nanotube composite based 36° YX LiTaO 3 surface acoustic wave H 2 gas sensor

Poly-vinyl-pyrrolidone (PVP) is one of the actylene chemistry products founded by Prof Walter Reppe [1]. In most cases, PVP usually presents as an essential auxiliary, not an active substance itself [2]. Until recently, He et al. [3] has reported the application of PVP fibers as H2 gas sensor. Extending from the reported investigation, this work shows the gas sensing properties of PVP/MWNTs composite/36° YX LiTaO3 SAW device.

Indoor free space optical communications for aircraft passenger cabin

The use of infrared radiation as a medium for high speed and short-range application is proposed for communication in the aircraft passenger cabin since it does not cause any interference to aircraft navigation systems. In this paper: first of all, using Lamberts model, the power received at the receiver via single reflection propagation inside the cabin was modeled. Then, the free space loss which depends on distance and height of transmitter and receiver from ceiling was calculated. Thirdly, in order to estimate the multipath power penalty, from the impulse response model, the delays spread dispersions and mean delays, which are related to reflection patterns and the distance between transmitter and receiver were derived and modeled. Finally, ceiling bounce model was developed to obtain the impulse response and 3dB cut off frequency. After modeling in the passenger aircraft cabin, the results are the minimum power received and the maximum bud-rate that is available to be achieved.