Applied Mechanics and Materials Vol. 815

Abstract: We report the development of two epilayers namely the baseline highly strained channel and enhanced low gate leakage samples. The Hall data shows that the enhanced epilayer portraying higher sheet carrier concentration, but comparable carrier mobility in the 2-DEG layer, as compared to the baseline sample. The WinGreen simulation also conformed the enhanced epilayer advantages where wider Schottky barrier is observed and subsequently double carrier concentration is simulated in the channel. Both samples show low AuGe/Au Ohmic contact resistivity of approximately 0.16 Ω.mm. A tremendous advantage on 1 μm Schottky gate leakage is also recorded on enhanced epilayer where the leakage is more than seven times lower than that of the baseline sample. The resulted characteristics are much better than the reported submicron device, thus this device has find an important application in high-gain lossless transmission, especially in underwater optical communication system.

Abstract: This work is based on dual Mach-Zehnder interferometer with semiconductor optical amplifiers in both arms. The proposed flip-flop operates at a single wavelength. A bidirectional coupler is placed at the end of the system to observe the output at set and reset terminals. The signals modulate the injected photon rate in the SOAs thus forming photonic flip-flop function. The photon injection rate is modulated due to self-gain modulation and self-phase modulation that occur in the SOAs towards demonstrating optical bistability. Switching between states of the flip-flop occur at full width half maximum of 32 ps. The output power of this flip-flop is around 24.5 mW. It is observed that the switching energy can be adjusted to a low level by decreasing the injected currents into the SOAs. The injection and the input power are the two parameters that govern the whole operation of the designed flip-flop.

Abstract: This work focuses on the nondestructive fruit ripeness detection system at difference maturity stages. The study involved a two-step approach which is the absorption and reflection spectral analysis. In this system, light dependent resistor (LDR) is used as the light sensor and displayed on the LCD screen of its resistivity. Portable spectrometer is adopted for measuring the reflection and absorption before processed by simple electronic Arduino-based circuit. The results of the photonic ripeness detection system show that the ripe fruit has higher light reflection rate in comparison to the unripe fruit. If the average value of the resistance is in between 400-600 the fruit is classified as still in immature period. Where as the resistance of 610-800 indicates the fruit is matured. The growth of fruit determines the difference ripeness levels and its resistivity too.

Abstract: The aim of the project is to implement a facial recognition system for access control to enter a room. The facial image captured by a webcam and then be detected/tracked using Haar face tracking algorithm. Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA) algorithm have been used for face recognition. The system was tested with 10 users from the member of a laboratory room. Each user registered 100 images for training of the PCA and LDA. The recognition rate achieved using PCA was 70% and 97% for LDA.

Abstract: This paper proposes a leak detection method using acoustic. The Hamming chirp signal injected into the pipeline system and the estimation of the leak location from the delay time passing by the reflection in the pipeline if there is a leak. By using Hilbert-Huang Transform (HHT), it can give a useful signal to verify the leak. HHT transforms Empirical Mode Decomposition (EMD) and Hilbert Spectrum analysis to perform time-frequency analysis. The leak location can be detected by multiplying by the speed of sound. This simple method gives accurate leak location and easy to implement.

Abstract: This paper investigates the performance of a real-time self-tuning speed controller designed to track and regulate at various engine speeds. The controller was tested with an automotive engine fuelled with petroleum diesel and and palm oil biodiesel (Palm Methyl Esters) within speed range of 1800 rpm to 2400 rpm. A self-tuning control algorithm based on pole assignment method together with on-line model parameters estimation strategy based on the recursive least squares method are adopted. The ability of the controller to track, regulate at various engine speed and also to reject disturbances applied for both type of fuel are compared and presented. The results confirmed that the controller performed very satisfactorily.

Abstract: The successful optimization process of machining parameters is significantly important to the green manufacturing industries. However, the optimization process of machining problem is difficult to solve using conventional optimization techniques. Hence, the computational approach methodology such as Harmony Search (HS) is considered as an alternative way for optimization process in manufacturing industries. This paper discusses the overview of Harmony Search (HS) to optimize the machining parameters in machining process. Example of previous works that applied HS algorithm in machining optimization problems are also discussed.

Abstract: This paper presents a review on gravitational search algorithm (GSA). Nowadays, GSA has been used in various engineering studies such as production cost, production time, power consumption and emission. The GSA also mainly focuses to solve the problem related to optimization, modeling, scheduling and clustering. This paper also highlights the current researches using improved GSA.

Abstract: With the development of offshore fishing and deep sea exploitation intensifies, floating offshore remote terminal (FORT) which having many advantages can better adapt to the complicated environment of deep sea in numerous offshore platform. Due to the hull likely to to resonance phenomenon, FORT has more intense motion compared to other hull form types. Therefore, the main challenge of FORT in the deep sea operation is to design effective mooring system. This paper introduced the dynamic response by utilizing the computational effort associated with time-domain simulation of single anchor leg mooring (SALM). The influenced or the effect of significant wave height (SWH) over the structure is discussed. It is shown that a comparison of different SWH value in terms of their stability properties is sufficient and adequate; relative merit is assessed through comparison of full systems that have been designed to minimum cost, and to common performance specifications. It is found that single point or catenary systems, can outperform both static and dynamic solutions at the preliminary stage. Moreover, the results indicated that the position ability and mooring strength of SALM system whose intermediate material is studless chain of catenary mooring system on the premise that satisfies API specification at the same time.

Abstract: The industry of oil and gas will be always constantly adapting to changes over time, whether in terms of technology, market demands or price thus increase the operational risk and danger in the operation. The purpose of this research is to study on the current practices of safety management implemented in the upstream part in the industry and its effectiveness, altogether to emphasize on the importance of safety management system in the industry. This research focus on the implemented safety management in upstream sector of oil and gas industry especially in PETRONAS Carigali Sdn. Bhd in Malaysia and evaluate and investigate its effectiveness. Questionnaire survey is conducted regarding safety and the data and results gained from the survey are analysed using the Relative Importance Index (RII) and also by using Average Index (AI). The research put safety management as the main factor in preventing and reducing accidents and incidents to occur in industries of the oil and gas and emphasize on awareness and importance of managing safety in oil and gas industry.