Hydrology and Sediment Loading in a Degrading Natural Lake System in Malaysia

Hydrology and suspended sediment loading in the catchment of the natural Chini Lake (second largest natural lake in Malaysia) was investigated. Suspended sediment loads and discharge from seven selected feeder rivers were measured over a period of 1 year from January to December 2006. The river water flow rate during the sampling periods was relatively low, ranging from 0.001 to 1.31 m3/s or an average of 0.21 m3/s. The highest and lowest stream flow discharge rates were recorded from the Gumum and Cenahan River sub-catchment areas, respectively. The amount of sediment load ranged from 0.49 to 166.02 kg/km2/day or an average of 30.57 kg/km2/day in the study area. The highest sediment load was recorded in the wet season and the lowest in the dry season. Anthropogenic activities have significantly affected the hydrological functions and availability of the suspended sediments, and have thus influenced the variation in sediment output in the study area

Evaluation of Novel Bio-friendly Two-step Process in the Removal of Heavy Metals from the Wastewater

Two-step treatment technique was developed for the treatment of water by Pseudomonas aeroginosa in a bioreactor in a first phase and then the bacterial treated water was treated with the vetiver grass, cattails and water hyacinth in second phase. Two-step process of bioremediation of 13 days was found to be satisfactory for As, Ba, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn in compared to the direct treatments with vetiver grass, cattails and water hyacinth in 20 days. As the plants cannot work or tolerate the higher concentrations of heavy metals, so with the first step on an average 52.48% reduction of heavy metals were done within 5 days. It was observed that 100% removal of Pb was found by two-step process of Pseudomas aeroginosa with cattails and water hyacinth, respectively in 13 days, while 98.16% removal of Pb was found by direct plant treatment of water hyacinth in 20 days. It was clear that the two-step treatment for vetiver grass, cattails and water hyacinth were found as the most effective treatments

Transport of Electrons in Two-Dimensional Lateral Surface Superlattices

Magnetoresistances were measured in a wide range of asymmetric and symmetric two-dimensional lateral surface superlattices (2D LSSLs) and the detailed studies of the data using the existing models lead to the following conclusions. 1) In cases of strongly broken symmetry, different Fourier components do not independently contribute to the commensurability oscillations (COs) in striking agreement with the guiding centre drift model of D. E. Grant, A. R. Long and J. H. Davies [Physical Review B 61 (2000) 13127]. Moreover, it is found that the characteristics of the COs are defined by the asymmetry of the potential landscape as envisaged by this model. A previous semi-classical model [R. R. Gerhardts; Physical Review B 45 (1992) 3449] and a corresponding quantum mechanical calculation [F. M. Peeters and P. Vasilopoulos; Proceedings of 20th International Conference on the Physics of Semiconductors (ICPS-20), 1990, p. 1589] are both found to be unable to account for the data. 2) In stressed rectangular superlattices, for transport along the cube axes, change of gate bias from large positive to less positive changed the dominant Fourier component in the 2D periodic potential from a diagonal to an axial Fourier component and accordingly the guiding centre drift direction switched from a diagonal to the appropriate axial direction manifested by the change of the period of COs from that of diagonal Fourier component to that of the dominant axial Fourier component. When the dominant diagonal and axial Fourier components were nearly equal in amplitude, the switching was observed by change of magnetic field at a constant gate bias, as change in the magnetic field changed the dominant Fourier component in the magnetic field dependent effective potential. These results are in complete accord with the guiding centre drift model of D. E. Grant, A. R. Long and J. H. Davies [Physical Review B 61 (2000) 13127]. Again, the previous semi- classical model [R. R. Gerhardts; Physical Review B 45 (1992) 3449] and a corresponding quantum mechanical calculation [F. M, Peeters and P. Vasilopoulos; Proceedings of 20th International Conference on the Physics of Semiconductors (ICPS-20), 1990, p. 1589] are both found to be unable to account for the data, particularly the phenomenon of switching. 3) In 2D LSSLs containing symmetric potential landscapes, different Fourier components do independently contribute to COs confirming the quantum mechanical calculation of F. M. Peeters and P. Vasilopoulos [Proceedings of 20th International Conference on the Physics of Semiconductors (ICPS-20), 1990, p. 1589]. An interplay between the semi-classical model of D. E. Grant, A. R. Long and J. H. Davies [Physical Review B 61 (2000) 13127] and the said quantum mechanical model is found to be necessary to account for the suppression of the amplitude of COs. 4) Asymmetry suppresses quantum mechanical effects in asymmetric 2D LSSLs. 5) Symmetric, stressed, short period and high mobility 2D LSSLs showed a characteristic amplitude modulation of COs whenever one flux quantum hle passed through 1, 2, 3, ... unit cells of the lattice. This phenomenon is found to be related to flux quantization. (Abstract shortened by ProQuest.)

Water Quality Index: an Indicator of Surface Water Pollution in Eastern part of Peninsular Malaysia

Abstract Water quality deterioration in eastern part of peninsular Malaysia especially in Gebeng i

Heavy metals pollution sources of the surface water of the Tunggak and Balok River in the Gebeng Industrial Area, Pahang, Malaysia

The heavy metal contamination of surface water is regarded as one of the most serious environmental hazards. The purpose of this study is to identify the origins of 10 heavy metals found in surface water in the Gebeng industrial area rivers. The samples were gathered over the course of a year at ten stations along the Tunggak and Balok rivers. According to the Malaysian heavy metals standard, the surface water of the Gebeng rivers was contaminated with six heavy metals: Cd, Co, Cu, Pb, Mn, and Ni. Inductively Coupled Plasma Mass Spectrometry was used to analyze the data. SPSS version 22.0, a multivariate statistical tool, was used to identify the sources. The heavy metals have been divided into three components using principal component analysis, indicating that the pollution is due to anthropogenic causes. The stations were grouped into three groups using cluster analysis, with high pollution loading falling under industrial zone stations (IZ1, IZ2, and IZ3), indicating pollution from industrial sources. In general, the findings of this research will be useful in future studies aimed to reduce heavy metal contamination in the Gebeng rivers

Estimation of the Rate of Soil Erosion in the Tasik Chini Catchment, Malaysia Using the RUSLE Model Integrated with the GIS 1

Abstract: The Tasik Chini Catchment, located at the southeast region of Pahang, Malaysia is experiencing soil erosion problems which are of environmental concern. So a study was conducted that involved the integration of the Revised Universal Soil Loss Equation (RUSLE) with the Geographic Information System (GIS) to estimate potential soil loss and identify erosion risk areas. Values for the model on rainfall erosivity (R), topographic factors (LS), land cover (C) and management factors (P) were calculated from rainfall data, together with the use of topographic and land use maps. Soil was analyzed for obtaining the soil erodibility factor (K). Physical properties such as particle size distribution, texture, hydraulic conductivity and organic matter content (OM) were analyzed to support the erosion rate analysis. The mean soil erodibility factors varied from 0.03 to 0.30 Mg h MJ -1 mm -1 . From a total of eleven soil series studied, soil erosion results showed that the five soil series with low rate of soil loss were: Tebok, Lating, Bungor, Kekura and Gong Chenak. Two soil series with moderate soil loss were Serdang and Prang. Two soil series with moderately high rate of soil loss were Kuala Brang and Rasau. The Malacca soil series had high erosion rate. The worst-case scenario was the Kedah soil series. The soil erosion potential zones were classified into five classes namely very low, low, moderately high, high and very high soil loss. The results indicated that 71.54% of the study area lay within the very low erosion risk class, 2.94% in the low erosion risk class, 3.38% in the moderately high erosion risk class, 1.45% in the high erosion risk class and 13.25% in the very high erosion risk class. This high erosion rate is expected to generate high sediment yield influx into the water bodies of Tasik Chini making the lake shallower and perhaps even non existent in the near future if precautionary measures are not taken

Anti-fungal efficacy of aqueous leaf extracts Neem (Azadirachta indica) in the treatment of tap water

High-quality drinking water coming from treatment plants is susceptible to pollution and severe deterioration due to the drinking water delivery system prior to access to consumers’ faucets. The results of this study confirmed that Neem leaves extract and chlorine at all concentrations had antifungal activity during tap water treatment. This study has provided excellence about the ability of Neem leaves extraction and chlorine as a disinfectant for Rhodotorula mucilaginosa and Aspergillus spp. in treating tap water. The most notable factors were the dosage, time, and agitation selected to evaluate their effects on reducing the development of fungal communities in drinking water using the central composite design (CCD) in the response surface methodology (RSM). The CCD was performed with a 2 complete central composite design with five different stage coordinate components. Because the Neem leaves can be processed locally and should also be encouraged for use in water treatment. This will eventually reduce the high costs and health risks associated with chemical water treatment. This technology is cheap, conventional, readily available, and suitable for rural areas, as nature’s biological methods generate no treatable waste

The antifungal efficiency of Moringa oleifera seed extracts for tap water treatment

Water must be pure and free of any contaminants for human consumption. However, due to indiscriminate human activity, its quality has worsened, resulting in many illnesses that plague humanity, particularly in developing nations. Promising water treatment procedures are considerably more expensive, and many of the disinfectants now in use are toxic, making the hunt for safer organic alternatives even more difficult. Moringa seeds have long been used to clean drinking water and minimize the health concerns associated with microorganisms in rural communities. Using central composite design (CCD) in response surface technique, the parameters identified as the essential components, dose, duration, and agitation, were chosen to assess their influence on eradicating the growth of fungal communities in the drinking water by response surface methodology (RSM). The CCD was done with two complete factorial combination components at five distinct levels. The typical two fungi widespread in the tap water samples have selected Aspergillus sp. (73%) and Rhodotorula mucilaginosa (63%). Fungal mycelia growth gradually decreased with increased concentration of Moringa oleifera seeds extract and chlorine on Rhodotorula mucilaginosa and Aspergillus sp. The modified determination coefficients (adj R2) for the CFU of Moringa seeds were also 0.8122 and 0.8405. This study aims to highlight the performance activity of Moringa seeds while treating tap water instead of using rapid usage of chlorine in the traditional method. This study found that Moringa oleifera extract seeds and chlorine have antifungal action against disinfectants at all concentrations. Using Moringa oleifera seeds extract and chlorine as a disinfectant on Rhodotorula mucilaginosa and Aspergillus spp. in treating tap water is a viable alternative. This method would significantly reduce the high costs and health concerns of current chemical water treatment methods. The method is traditional and simple to apply, making it suitable for rural regions. It also produces no non-treatable wastes because it is biological

An overview of effect of activation functions on training and performance of artificial neural network modelling

This paper presents an overview of the effect of the activation functions on the training and performance of artificial neural network modelling. An artificial neural network's activation functions are mathematical formulas that are essential to its design. Activation functions are a critical component of artificial neural networks since they impact the performance of the ANN model to a considerable extent. It is a function that is utilized in order to obtain the output of the node. In an artificial neural network, defining an activation function is critical, as it directly affects the network's success rate. A concise summary of some of the most frequent activation functions that are utilized in neural networks. Activation functions are defined, their properties are compared, and their advantages and disadvantages are described in this paper. This review is provided with the definitions, features, performance comparisons, merits and demerits and applications of activation function in various areas. The activation function has an impact on the development of ANN models. It is found that sigmoid, Tanh and ReLU are the most used activation function and give better performance compared to others

Assessment of physico-chemical parameters of surface water quality in Chini Lake Area, Pahang, Malaysia

Because of pollution from mining and agriculture that has been poured into the surface water, the contamination level in the Chini lake water-shed has increased. As a result, the current study was conducted to assess the surface water quality of Chini Lake in Pahang, Malaysia. The principal compo-nent analysis was utilized to classify the investigated data into five categories based on the sources of pollutants, and the correlation between all of these groups was shown. Cluster analysis, on the other hand, divided ten monitoring sites into two groups (high and moderate pollution). The experimental results were analyzed and categorised using the Department of Environment Water Quality Index (DOE-WQI) in accordance to the Malaysian National Water Quality Standard (NWQS). The most contaminated parameters in the study area were pH and ammoniacal nitrogen, according to the findings. In fact, the worst situation (class III) was found at station T4, where tributaries were heavily con-taminated, followed by farmland and mining areas at stations 3 and 4. Finally, according to the WQI Malaysia, the lake water quality was classed as class II. Furthermore, the water quality has been confirmed to be acceptable for safe human body contact and a variety of recreational activities