Assessment parameters for coal-fired generation plant site selection

In order to meet future demand for electricity, Tenaga Nasional Berhad (TNB) is committedto the long-term strategic planning in locating suitable sites for future development of power stations.Site selection is an important process in the early planning stage of any power plant development asit will have significant implications on the capital investment, operational as well as the environmentand socio-economic costs of the power plant.The aim of this presentation is to briefly describe the ten (10) main assessment parametershaving the most profound effects on the selection of potential coal-fired generation plant sites.These assessment parameters were derived based on a survey of approximately 40 experts, comprisingfrom various specialists such as engineers from TNB, senior officers from Department Of EnvironmentMalaysia (DOE), scientist from University Malaya (UM) and a number of other independentconsultants

Single and multiple transceiver simulation modules for free-space optical channel in tropical Malaysian weather

Free space optics (FSO) is an optical communication technology that uses light propagating in free space to transmit data for telecommunications or computer networking, and is exposed to atmospheric attenuation, like absorption and scattering. These types of attenuations seriously degrade the strength of transmitted signal, especially when single beam FSO system is used. So to overcome this problem, a multiple beam FSO transceiver system has become dominance and is usually used. In this paper simulation models are obtained by using average rain attenuation which is evaluated from the five months collected rain intensity data. These models are obtained to demonstrate the results concerning link distance and received optical power of using multiple beam FSO system and comparing it with single beam FSO system. Comparison is carried out in terms of signal to noise ratio (SNR), geometrical losses, atmospheric losses, and bit error rate (BER). From the results it is clear that, by using up to four beams has improved geometrical loss, sensitivity of the receiver, SNR, and link distance

Application of the Grey-Taguchi method to the optimization of metal injection molding (MIM) process

The Grey-Taguchi method was adopted in this study to optimize the injection molding parameters for the MIM green compacts with multiple quality performance. A Grey relational grade obtained from the Grey relational analysis is used as the quality performance in the Taguchi method. Then, the optimum injection molding parameters are determined using the parameter design proposed by the Taguchi method. The result concluded that the mold temperature (D) is very significant, by the fact that the ANOVA shows its contribution to excellent surface appearance as well as strong and dense green compacts is 38.82%

Importance of Silicon and Mechanisms of Biosilica Formation in Plants

Silicon (Si) is one of the most prevalent macroelements, performing an essential function in healing plants in response to environmental stresses. The purpose of using Si is to induce resistance to distinct stresses, diseases, and pathogens. Additionally, Si can improve the condition of soils, which contain toxic levels of heavy metals along with other chemical elements. Silicon minimizes toxicity of Fe, Al, and Mn, increases the availability of P, and enhances drought along with salt tolerance in plants through the formation of silicified tissues in plants. However, the concentration of Si depends on the plants genotype and organisms. Hence, the physiological mechanisms and metabolic activities of plants may be affected by Si application. Peptides as well as amino acids can effectively create polysilicic species through interactions with different species of silicate inside solution. The carboxylic acid and the alcohol groups of serine and asparagine tend not to engage in any significant role in polysilicates formation, but the hydroxyl group side chain can be involved in the formation of hydrogen bond with Si(OH)4. The mechanisms and trend of Si absorption are different between plant species. Furthermore, the transportation of Si requires an energy mechanism; thus, low temperatures and metabolic repressors inhibit Si transportation

Recent changes in extreme rainfall events in Peninsular Malaysia : 1971-2005

This paper assesses recent changes in extremes of annual rainfall in Peninsular Malaysia based on daily rainfall data for ten rain-gauged stations over the period 1971-2005. Eight indices that represent the extreme events are defined and analyzed. Maps of trends for these indices, which are extreme dry spell (XDS), extreme rain sum (XRS), extreme wet day intensities at 95% and 99% percentiles (I95 and I99), proportion of extreme wet day to the total wet day (R95 and R99), and frequency of extreme wet day at 95% and 99% percentiles (N95 and N99), were analyzed based on annual data and seasons. When the indices are evaluated annually, the Mann-Kendall and linear regression trend tests showed increasing trends in the extreme intensity indices (I95 and I99) at two stations. A significant decrease in N99, associated with the frequency of extremely wet days, was observed at 60% of the stations. The change points for these indices are found to occur in the period of the 1980s. There is no significant trend detected for XDS, XRS, and proportion of extreme rainfall over total rainfall amount indices during the period considered in this study. Descriptive analysis of indices during the monsoon period showed that the annual spatial pattern for the peninsula is very much influenced by the northeast monsoon where the highest mean values for majority of the indices occur during this time period

Spatial trends of dry spells over Peninsular Malaysia during monsoon seasons

This study aims to trace changes in the dry spells over Peninsular Malaysia based on the daily rainfall data from 36 selected rainfall stations which include four subregions, namely northwest, west, southwest, and east for the periods of 1975 to 2004. Six dry spell indices comprising of the main characteristics of dry spells, the persistency of dry events, and the frequency of the short and long duration of dry spells will be used to identify whether or not these indices have increased or decreased over Peninsular Malaysia during the monsoon seasons. The findings of this study indicate that the northwestern areas of the Peninsular could be considered as the driest area since almost all the indices of dry spells over these areas are higher than in the other regions during the northeast (NE) monsoon. Based on the individual and the field significant trends, the results of the Mann–Kendall test indicate that as the total number of dry days, the maximum duration, the mean, and the persistency of dry days are decreased, the trend of the frequency of long dry spells of at least 4 days is also found to decrease in almost all the stations over the Peninsula; however, an increasing trend is observed in the frequency of short spells in these stations during the NE monsoon season. On the other hand, during the southwest monsoon, a positive trend is observed in the characteristics of dry spells including the persistency of two dry days in many stations over the Peninsula. The frequency of longer dry periods exhibits a decreasing trend in most stations over the western areas during both monsoon seasons for the periods of 1975 to 2004