Effects of Length and Diameter of Open-Ended Coaxial Sensor on its Reflection Coefficient

This paper presents a calibration technique for a coaxial sensor using a transmission signal approach. The sensor was fabricated from commercially available RG402/U and RG405/U semi-rigid coaxial cable. The length of the coaxial sensor was correlated with the attenuation and standing wave inside the coaxial line. The functions of multiple reflection amplitude and tolerance length with respect to the actual length of coaxial line were empirically formulated using regression analysis. The tolerances and the undesired standing wave which occurs along the coaxial line were analyzed in detai

Integrating vocational training in culinary arts and Islamic studies at juvenile rehabilitation centres: Malaysian experience

The Juvenile Rehabilitation Centres (JRC) in Malaysia aims to provide shelter, counselling and skills training to juveniles specifically for those who wish to transform themselves from the regrettable misdeeds they have committed. At JRCs, an integrated Culinary Vocational Training and Islamic education forms part of their training curriculum. The skills acquired should enable trainees to secure jobs upon completion of training. However, there are some training institutions that lack systematic training structures resulting in trainees becoming less skilful in both vocational and Islamic education. The objective of this research is to identify the effectiveness of an integrated Culinary and Islamic Education curriculum implemented at JRCs in Malaysia. This is a descriptive survey and data was obtained using questionnaire and interview. Respondents comprised 92 trainees, four managers, four culinary trainers and four Islamic education teachers, all from four different JRCs. The findings show that the trainees are happy with their trainings that brought about positive effects for them. Some suggestions have been made to provide improvements in the implementation of the course among them the inclusion of prayers in the Islamic education syllabus

Characterization and intraspecific variation of Fusarium semitectum (Berkeley and Ravenel) associated with red-fleshed dragon fruit (Hylocereus polyrhizus [Weber] Britton and Rose) in Malaysia

A total of 79 isolates of Fusarium semitectum were characterized by morphological and IGS-RFLP analysis to assess its intraspecific variation. Based on morphological characteristics, the isolates of F. semitectum were classified into 2 distinct groups, morphotypes I and II. Morphotype I was characterized by longer macroconidia (3 - septate: 31.03 ± 2.57 ìm; 5 - septate: 40.17 ± 1.85 ìm), 0 - 7 septate with 5 - septate was the most common, absence of chlamydospores, presence of sporodochia, abundantfloccose mycelium, peach colony appearance, peach to orange pigmentations and fast growing. While isolates of morphotype II produced shorter macroconidia (3 - septate: 24.98 ± 1.87 ìm; 5 - septate: 35.24± 2.07 ìm), 0 - 5 septate with 3 - septate was the most common, with (56%) or without chlamydospores (44%), without sporodochia, abundant-floccose and abundant-powdery mycelium, beige to brown colonies, brown to dark brown pigmentations and slow growing. Corresponding to the morphological characterization, IGS-RFLP analysis indicated that the 79 isolates could be divided into 2 different clusters assigned as RFLP groups I and II. 49 IGS haplotypes were produced by 8 restriction enzymes(AluI, Bsu15I, BsuRI, Eco881, Hin6I, MspI, PstI and TaqI) which indicated a high level of intraspecific variation and polymorphism among the 79 isolates. This is the first report of F. semitectum associated with H. polyrhizus

Optical Fiber Bending Detection on Long Distance OPGW using OTDR

In Malaysia, thousands of kilometers of Optical Ground Wire (OPGW) have been installed by a utility company. For long distance fiber cable, there is a possibility of optical fiber to bend with very small radius especially in joint closures which caused optical power to attenuate. This attenuation is known as ‘bend losses. Bend loss increases the total power attenuation of optical fiber. In addition, for long distance fiber cable, it is important to avoid any extra loss as the fiber itself attenuates 0.2 to 0.35 dB/km and splice loss about 0.1 dB each. Hence, in this study, the method of detecting bend loss as well as optical fiber bending is presented. The result of this study is expected to allow fiber industry players to determine the exact location and proper rectification can be done to solve bend loss problem

Multi slot amplitude coding technique for high speed optical fiber communication system

The rapid progress of the high speed optical communications system is driven by the exponential growth of users demand on information and services. The trend towards high speed and high capacity transmission system are multiplexing technique such as electrical time division multiplexing (ETDM) and duty cycle division multiplexing (DCDM). Unfortunately, ETDM bit rate is limited by the speed of electronic devices and DCDM suffers from increased spectral width when the number of tributary increased. Therefore, in this research, a new multiplexing technique is proposed, known as Multi Slot Amplitude Coding (MSAC). In this technique, three, four and five tributaries can be achieved with less number of slots compared to DCDM. The performance of 310 Gbit/s MSAC is -26 dBm for receiver sensitivity (RS) and 25.5 dB for optical signal-to-noise ratio (OSNR). The improvement of 3.5 dB for RS and 3.7 dB for OSNR are obtained when optimize level spacing is implemented. When compared to DCDM, the spectral width is reduced by around 25%, not less than 55% improvement of chromatic dispersion (CD) tolerance, 0.6 dB better RS, and 1.5 dB better OSNR. The spectral width for 310 Gbit/s, 410 Gbit/s and 510 Gbit/s MSAC is 60 GHz, which indicates improvement of spectral efficiency. Optical spectrum of MSAC has spectral line at 10 GHz to provide an accurate clock frequency at symbol rate. In addition the performance of MSAC technique is simulated under self phase modulation (SPM) effect. The result shows that the maximum launched optical power is +12.79 dBm and +12.62 dBm for 50 km and 80 km standard single mode fiber (SSMF) with 100% compensation of dispersion using dispersion compensation fiber (DCF) at receiver. Moreover, SPM threshold improves around 2.7 dB when adopting the pre and post dispersion compensation method

MEDIA OPTIMIZATION FOR BIOPROTEINS PRODUCTION FROM CHEAPER CARBON SOURCE

There are high demands for animal and human food supply especially protein, which is an important dietary component. Agricultural wastes, cheap carbon sources- which are rich and have high energy, can be used for producing the value added bioprotein. A lab scale study was carried out to optimize the media composition for bioprotein production from a cheaper carbon source - wheat flour using potential strain, which was selected earlier by screening different microorganisms. The performance of the selected strain was enhanced by media optimization with varied substrate concentration, nitrogen sources and nutrient supplementation according to the central composite design from STATISTICA software. Statistical optimization was carried out to evaluate the polynomial regression model through effect of linear, quadratic and interaction of the factors. The maximum biomass produced was 21.89 g/L with optimum fermentation conditions of wheat flour (4 g/L), nitrogen concentration (0.5 g/L), nutrient concentration (0.1 g/L), and four days of fermentation

Suitability of using palm oil mill effluent as a medium for lipase production

Lipases are enzymes that can be secreted by several microorganisms using agro-industrial residues as potential substrates. This work screened ten microorganisms for their potential to produce lipase in palm oil mill effluent (POME)-based medium. Among the 10 organisms, the most promising strain was Candida cylindracea (ATCC 14830) which showed appreciable activity both on agar plates and liquid cultures. Medium supplementation by NH4Cl and olive oil led to an enzyme activity of 2.07 U/ml. However, supplementation with organic nitrogen sources resulted in better enzyme activity. Addition of malt extract, peptone and olive oil into the medium greatly influenced the lipase production. Among the oils that were tested, olive oil was found to be the best for the expression of extracellular lipase at 0.5% (v/v) with an activity of 4.02 U/ml in an optimized POME supplemented medium.Key words: Lipase, agro-industrial residue, palm oil mill effluent, Candida cylindrace

Comparative study ofthe computational fluid dynamics and fluid structure interaction analysis in human airways flow

Numerous studies have been done in order to get the most accurate result that represents the flow characteristics inside the human trachea. Numerical method was the most favorite type of study chosen to simulate the model due to the complexity of the geometry and difficulties to get the real trachea to do the experimental works. In this study, one actual healthy model of human trachea was reconstructed in order to compare, the different of the velocity and pressure distribution between two types of numerical modeling analysis: Computational Fluid Dynamics (CFD) and Fluid Structure Interaction (FSI) analysis. The model was extracted using the Computed Tomography (CT) scan images to maintain the realistic geometry. Velocity, 1.24 m/s was used at the inlet and the variations of the velocity and pressure distribution along the trachea were observed. The results shown that, the implementation of the FSI technique did produce different result and flexibility of the structure wall did influence the distribution of the velocity and pressure along the trachea

Nonlinear Dynamics of Chaotic Attractor of Chua Circuit and Its Application for Secure Communication

The Chua circuit is among the simplest non-linear circuits that shows most complex dynamical behavior, including chaos which exhibits a variety of bifurcation phenomena and attractors. In this paper, Chua attractor's chaotic oscillator, synchronization and masking communication circuits were designed and simulated. The electronic circuit oscilloscope outputs of the realized Chua system is also presented. Simulation and oscilloscope outputs are used to illustrate the accuracy of the designed and realized Chua chaotic oscillator circuits. The Chua system is addressed suitable for chaotic synchronization circuits and chaotic masking communication circuits using Matlab® and MultiSIM® software. Simulation results are used to visualize and illustrate the effectiveness of Chua chaotic system in synchronization and application of secure communication.  Keywords: chua nonlinear circuit, chaotic attractor, chaotic synchronization, secure communication