Investigation of electrical potential and electromagnetic field for overhead high voltage power lines in Malaysia

The exposure of human body to electric field and magnetic field could cause biological effects, including changes in functions of cells and tissues and subtle changes in hormone levels, which may or may not be harmful. The aim of this study was to analyze and compute the amount of electrical potential, electric field and magnetic flux density at a certain point and distance from the overhead high voltage power lines of 132 and 275 kV in Malaysia. An analytical calculus method is proposed in order to accomplish this study. The models of the power lines were constructed using the actual physical dimensions of the towers. The results show that the exposure levels of the electromagnetic fields to the public is low if they stay more than 30 m away from the power lines. For the live-line worker, the exposure to the high electric and magnetic field could endanger their body if they stay too close to the conductor. The evaluations of the electrical potential, electric field strength and magnetic flux density are done using the Matlab environment. Matlab’s Graphical User Interface (GUI) techniques are developed as an easy and user-friendly tool to be used

Synthesis of fibrous silica tantalum (FSTa) for photooxidative desulphurization

The photooxidative desulphurization (PODS) of dibenzothiophene (DBT) was examined under visible light using fibrous silica tantalum (FSTa), tantalum oxide doped fibrous silica (Ta/KCC-1) and commercial tantalum oxide (Ta2O5). FSTa was synthetized using hydrothermal method, while Ta/KCC-1 was obtained via a wet impregnation method. The catalysts were examined by field emission scanning electron microscopy (FESEM), X-ray Diffraction (XRD) and UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). It was shown that the FSTa possesses the highest photocatalytic performance (70.2%), due to its fibrous structure, well-dispersion of Ta, as well as its narrower band gap. These traits impact on the photocatalysis by promoting the deposition of the DBT on the catalyst, allowing the efficient transfer of charge carrier and preventing the electron-hole recombination

Widely tunable Raman ring laser using highly nonlinear fiber.

An all-optical widely tunable Raman fiber laser has been realized by incorporating a highly nonlinear fiber in a ring cavity. By feedback a portion of Raman Stokes wave back into the highly nonlinear gain medium, a Raman fiber laser is generated. We found that the lasing wavelength of Raman fiber laser can be tuned from 1537 to 1568 nm with peak power fluctuation within 1 dB, giving a total wavelength tunability of 31 nm. The optical signal-to-noise ratio is found to be wavelength dependent, and the highest optical signal-to-noise ratio of about 59 dB is recorded. The lasing threshold of the Raman fiber laser with this configuration is found to be as low as 300 m

A contemporary assessment on composite titania onto graphitic carbon nitride-based catalyst as photocatalyst

Titanium dioxide (TiO2) has drawn widespread interest by researchers as a precious semiconductor that is responsive towards photodegradation of various pollutants. This catalyst has its own limitations such as fast electron-hole recombination, wide band gap, and can only be utilised under ultraviolet (UV) region. In order to overcome these problems, the addition of a metal-free dopant is a common practice to prevent electron-hole recombination and enhance photodegradation under visible light. Among various types of metal-free catalysts, carbon nitride material has received much attention due to its numerous benefits such as good in terms of physical and chemical strength, as well as an attractive electronic band combined with a band gap (2.7 eV). This review summarised recent works in the development of titania incorporated with graphitic carbon nitride (g-C3N4) for enhanced photocatalytic activity

Beneficial interaction of copper oxide and fibrous silica for enhanced photocatalytic desulphurization

Photocatalytic desulphurization (PDS) is considered as a promising technique to remove hazardous sulphur compounds from fuel oil due to its high catalytic activity, safety, low energy consumption, and low cost. In this work, fibrous silica KCC-1 was synthesized by hydrothermal method followed by incorporation of CuO by electrolysis. The catalyst was used for PDS of dibenzothiophene (DBT). The presence of bicontinuous concentric lamellar morphology with uniform spherical shape was confirmed by FESEM analysis. The phase and crystallinity of the catalysts was investigated by XRD, while the band gap energy was determined by UV-Vis DRS. The PDS performance of CuO/KCC-1 was compared with KCC-1, CuO/SiO2 and SiO2. It was observed that the photoactivity of CuO/KCC-1 was higher than other catalysts (62.6%), which is mainly due to its fibrous morphology and appropriate band gap energy, as well as synergistic role of both CuO and KCC-1. This fibrous type catalyst could be a promising candidate for environmental purification specifically in the sulphur removal

Effect of carbon-interaction on structure-photoactivity of Cu doped amorphous TiO2 catalysts for visible-light-oriented oxidative desulphurization of dibenzothiophene

Amorphous TiO2 (AT) was successfully prepared via the sol-gel technique, using different titanium sources followed by incorporation of copper via the electrochemical method to give CuO/TiO2 (CAT) catalysts. The catalysts were characterized via XRD, N2 physisorption, FTIR, TEM, EDX, XPS, ESR and UV–Vis DRS. The results verified that the use of different titanium precursors have profound effect on the physicochemical properties of the AT catalysts. Further one-pot self-doping carbon from titanium precursor during the addition of copper could greatly enhanced the photocatalytic activity of CAT on the oxidative desulphurization of dibenzothiophene (DBT). 15 CATTBOT exhibited the best performance mainly due to the narrowest band gap and higher numbers of O–Ti–C and Ti–O–C bonds, as well as appropriate amount of Ti3+ surface defects (TSD). These abovementioned properties offered good mobility of electron-hole pairs and/or trap the electrons for enhancement of photoactivity under irradiation of visible light. Kinetic studies showed that the photocatalytic oxidative desulphurization of DBT followed the pseudo-first order Langmuir-Hinshelwood model, where the adsorption was the controlling step. It is believed that these results could contribute to the synthesis of various supported catalysts for numerous applications specifically in removal of sulphur containing compounds in fuel oils

Directing the amount of CNTs in CuO–CNT catalysts for enhanced adsorption-oriented visible-light-responsive photodegradation of p-chloroaniline

Copper oxide (CuO, 10–90 wt%) was loaded onto carbon nanotubes (CNTs) by electrosynthesis method. The catalysts (CuO/CNT) were characterized by XRD, nitrogen adsorption–desorption, ESR, FTIR, Raman, and XPS spectroscopy. The results indicated that a lower amount of CuO was dispersed well on the CNT, while higher loading was agglomerated, producing large-size crystallites, hence resulting in lower specific surface area. Adsorption studies revealed that the isotherms are fitted well with the Langmuir model. Moreover, the n value that was obtained from Freundlich model indicated that adsorption process is chemisorption. Photodegradation of p-chloroaniline (PCA) under visible light irradiation demonstrated that the 50 wt% CuO/CNT catalyst gave the highest degradation (97%). It was concluded that C–N moieties of PCA were chemisorbed on the catalyst prior to photodegradation, while the Cu–O–C bonds, surface defects and oxygen vacancies were the main active site in enhancing the subsequent photodegradation. The kinetics of photodegradation were correlated with pseudo-first-order model, verifying the surface reaction was the controlling step. Remarkable mineralization results of PCA were attained by TOC (89.1%) and BOD5 (50.7%). It was also evidenced that the catalyst has a good potential toward degradation of various endocrine disruption compounds

Seamless tuning range based-on available gain bandwidth in multiwavelength Brillouin fiber laser.

We experimentally demonstrate a simple widely tunable multiwavelength Brillouin/Erbium fiber laser that can be tuned over the entire C-band, thereby greatly improving the tuning range limitation faced by the previous Brillouin-erbium fiber laser architectures. Tuning range of 39 nm from 1527 nm to 1566 nm, which is only limited by the amplification bandwidth of the erbium gain was successfully achieved. At Brillouin pump wavelength of 1550 nm and 1480 nm laser pump and Brillouin pump powers of 130 mW and 2 mW respectively, all the generated output channels have peak power above 0 dBm, with the first output channel having a peak power of 8.52 dBm. The experimental set up that consists of only 4 optical components, is simple, devoid of the complex structure employed previously to enhance the tunability and feedback mechanism normally associated with multiwavelength Brillouin-erbium fiber laser sources. The generated output channels are stable, rigidly separated by 10 GHz (0.08 nm)

Continuous wave tunable fiber optical parametric oscillator with double-pass pump configuration

We demonstrate a continuous wave tunable fiber optical parametric oscillator in a Fabry–Perot cavity consisting of a 500-m highly nonlinear fiber. In this work, the pump propagates in both directions together with the signal, thus making full use of its parametric gain. The resultant laser peak power is uneven across the wavelength range of interest due to wavelength-dependent phase modulation by the single-mode fiber sections in the cavity. This can be solved by filtering the idler spectral component from the oscillating cavity

Multilevel Wavelet Decomposition Watermarking Techniques

The merging of computer and communication technologies offer substantial new opportunities for processing and distribution of digital media. Along with powerful software and new devices such as digital cameras, scanners and printers, duplication, distribution, creation and manipulation of images can be easily and cheaply done. The protection of ownership and the prevention of unauthorized tampering of images are becoming increasingly important concerns to multimedia content owners especially when he content is to be made available through the internet, which is unsecured. Digital watermarking is considered by many a potential solution to this problem. It is a process which embeds some characteristics data in a image in advance which later can be extracted that can be used for authentication or proof of ownership. This paper proposed a combination of spread spectrum encoding of the embedded message and wavelet transform-based invariants for digital image watermarking. Using the proposed method, we investigated the effect of using different values of transparency of the original image. The experimental results show that the imperceptibility and robustness are guaranteed using the proposed technique