Design of sediment oxygen demand (SOD) 'in-situ' measuring chamber and its application in several rivers

Sediment oxygen demand is defined as the rate of dissolved oxygen removal from the water column by the decomposition of organic materials in the bottom sediments. Accurate SOD rates are important, as they will allow for more precise permits specifications and therefore the degree or level of wastewater treatment needed. The "in situ" SOD chamber designed for the study was adapted from an earlier design by the USEPA (Hatcher, 1986). Two sets of chambers of differing sizes were fabricated and used to measure the SOD levels in several rivers and a small lake. These measurements could be used for the calibration and validation water quality models. Another applied usage of the SOD chamber was for the management of aquaculture ponds. The knowledge of the SOD levels at the bottom of the aquaculture ponds will allow for a more systematic pond-cleaning schedule

Effects of Logging on Streamwater Quality and Solute Input-Output Budgets in Small Watersheds in Peninsular Malaysia

The effects of selective logging on streamwater quality and solute budget s were investigated using three small catchments: C1, C2 and C3. After a three-year calibration period,Cl and C3 were logged using" unsupervised" and "supervised" logging methods respectively, whereas C2 was left as control. Several control measures were imposed in the supervised C3 but none in the unsupervised C1. During the calibration period the levels for most of the streamwater quality parameters measured were within the standards for potable water. The exceptions were colour, turbidity and iron.Significant increases in pH, specific electrical conductivity, hardness, suspended solids, alkalinity, turbidity, dissolved solids, silicate, calcium, iron,and sodium were recorded in the unsupervised C1. The levels for colour and nitrate were also elevated initially but recovered to background values within a year. In contrast, in the supervised C3, significant changes were detected only for hardness, magnesium and iron. The impact of logging was enhanced during the wet months especially for suspended solids, turbidity and iron

Assessment of Impact on Landscape Development to Ecological Service Values and Goods Using Integrated Remote Sensing and GIS Techniques

Amongst the impacts of converting forest to agricultural activities is the degradation of ecology service values and goods (ESVG). Impacts on ESVG can be devastating in environmental, biological, and socio-economics manners. This paper highlights the study undertaken on the impacts of agricultural development in 0.8x106 ha of forest dominated landscape in Pasoh Forest Region (PFR), Malaysia, within period of 8 years from 1995 to 2003. Three folds of impacts on agricultural development examined and analysed are: (i) relationship of total soil loss and changes in land use pattern, (ii) mapping trends of ESVG for PFR in 1995 and 2003, and (iii) risk assessment of ESVG based on simulation of converting 339x103ha of primary forest into mass-scale oil palm plantation. Results of this study indicated that although only minor changes of about 1464ha (~0.2% of PFR) of primary forest was converted to agricultural activities, it have significantly increased the total soil loss from 59x106 to 69x106 t/ha/yr. The mean rate of soil loss within PFR is 0.8x106 t/yr, and if translated into ESVG term, costing US$4.8x106/yr. However, majority of the soil loss within all land use classes are within range of very low - low risk categories (<10 t/ha/yr). Estimated cost of ESVG for PFR was US$179x106 in 1995, declined to US$114x106 in 2003 due to 0.2$963x106 and US$575x106, respectively. This difference, however, is only marginal when full 17 attributes of ESVG were considered

Passive and active assistive writing devices in suppressing hand tremor

Patients with hand tremor disease frequently experience difficulties in performing their daily tasks, especially in handwriting activities. In order to prevent the ingestion of drugs and intervention of surgeries, a non-invasive solution was presented to improve their writing capabilities. In this study, there were two novel inventions of the hand-held device named as TREMORX and Active Assistive Writing Device (AAWD) with the approaches of passive and active elements respectively. For validation, the patient with tremor was assisted in using a normal pen and TREMORX to perform a handwriting task at the sitting and standing postures. For AAWD, the active suppressing element was the servo motor to control the hand tremor act on the writing tool tip and an accelerometer will measure the necessary parameters values for feedback control signal. The classic Proportional (P) controller and Proportional-Integral- Derivative (PID) were presented. The P controller was tuned with a meta-heuristic method by adjusting the parameters into several values to examine the response and robustness of the controller in suppressing the tremor. The evaluation was based on decreasing the coherence magnitude on the frequency response analysis. To optimise the performances, two types of Evolutionary Algorithms (EA) were employed which were Genetic Algorithm (GA) and Particle Swarm Optimisation (PSO). The optimisation techniques were integrated into the PID controller system to generate the optimum performances in controlling the tremor. For the simulation study, the parametric model representing the actual system of the AAWD was presented. The main objectives of this analysis were to determine the optimum value of PID parameters based on EA optimisation techniques. The determined parameters for both optimisations were then injected into the experimental environment to test and evaluate the performance of the controllers. The findings of the study exhibited that the PID controller for both EA optimisation provided excellent performances in suppressing the tremor signal act on the AAWD in comparison to the classic pure P controller. Based on the fitness evaluation, the GA optimisation significantly enhanced the PID controller performance compared to PSO optimisation. The handwriting performance using both TRREMORX and AAWD was recorded and from a visual justification, it showed that the quality of legibility was improved as compared with using normal handwriting devices. These outcomes provided an important contribution towards achieving novel methods in suppressing hand tremor by means of the invention of the handheld writing devices incorporated with intelligent control techniques

Characteristics and application of the asymmetric slab waveguide in optical integrated circuit

In this chapter, consists of demand in optical networking for photonic components that meet performance criteria as well as economic requirements has opened the door for novel technologies capable of high-yield low cost manufacturing while delivering high performance and enabling unique functions. The most promising new technologies are based on integrated optics. Integration permits the parallel production of complex multif unction photonic circuit on asymmetric slab waveguide. This kind of waveguide has very important role for designing the integrated optical circuit. To obtain the high performance function, we need to observe the waveguide characteristic in transverse mode (TE mode and TM m ode), the waveguide structure, and materials. Hence, a thoroughly study on asymmetric slab waveguide is essential in future implementation of optical devices in optical network. Integrated optics is the technology of constructing optic devices and networks on substrates [1]. Integrated optics offers the capability of combining optics and electronic components on a single substrate to produce functional systems or subsystems. Within an integrated optic network, light is transferred between components by a rectangular dielectric-slab waveguide

Identification of rainfall temporal patterns

Temporal pattern for rainfall events is required in the design and evaluation of hydrologic safety for hydraulic structures. In this paper, a method of statistical cluster analysis is applied to identify event-based representative temporal rainfall pattern in fourteen stations in Johor. The 8 hour separation time of no rain is used to divide the 5 years rainfall data into individual rainfall event according to the monsoons. The analysis is implemented from the dimensionless mass curve ordinates as the attributes in statistical cluster analysis of the cumulative storm depth over the non-dimensionalized time. As a result, three representative rainstorm patterns are identified and classified under the two basic types of advanced-type (A) and central-peak type (C) for northeast and southwest monsoon. Meanwhile, only one basic type is identified to represent rainstorm pattern during the inter-monsoon that is advanced type (A). In addition, the rainfall pattern is dependent on rainfall depth and duration, season and geographical location by contingency table test. The rainfall information presently used for design in Malaysia is very dissimilar to the representative curves derived in this study. The identification of three representative rainfall temporal patterns according to the monsoon seasons in Johor can be used as a basis to stochastically generate the plausible rainfall hyetographs of the specified pattern in Johor

Nutrient and sediment transport from two different agriculture land uses

For the past decades, the number of research on Non Point Source (NPS) pollution has increased due to its nature being the major source of pollution to water degradation around the world. The study of NPS in Malaysia is scarce especially in agricultural areas. This research aims to provide quality and quantity of runoff pollutant loadings from an agricultural farm at a plot scale. Two plots were constructed at different land use (fruit orchard and vegetable farm). Tipping bucket flow gauges were installed at the end of each slope to measure runoff volume and collect water sample. The water samples were collected over a period of three months, immediately following rainfall events. Nine water parameter (Nitrite, Nitrate, Ammonia, Total Nitrogen, Phosphate, Total Phosphorus, Chemical Oxygen Demand, Total Suspended Solid, pH) analyses were conducted by using the DR5000 UV-Spectrometer. Result indicated that Total Suspended Solid (TSS) from fruit orchard is much higher while the nutrient and Chemical Oxygen Demand (COD) in vegetable farm is higher in comparison. COD is higher in vegetable farm runoff than fruit orchard since organic fertilizers such as chicken manure are applied. Runoff collected is much higher in the fruit orchard since no effective cover crop there. Overall, the results confirmed that runoff waters from agricultural areas are heavily polluted and could affect the nearby receiving water in long term if it is not monitored and controlled

Agriculture drainage affects river water quality

The acidic level of the freshwater is a major concern to water treatment plant operators. Extremely acidic freshwater could affect the operation of the treatment plant in many ways. The cost to neutralisation the water would increase and treatment scheduling would be more complicated. This paper reports the influence of agricultural drainage on river water quality in Bekok river system in Johor, Malaysia. The river is the sole source of freshwater supply to two water treatment plants located at the downstream reach of the river. Three water quality parameters, i.e. pH, Iron and Ammonia-N, were used as an indication parameter. Water samples collected from 16 different river reaches along the 20-km river were analysed. A significant decrease in pH was found near the water intake point, where most of the drained areas are located. The study also found that in general, the quality of the river water was better during low flow condition (non-rainy days) compared to high flow (rainy days). Multiple regression analysis showed that pH was significantly related to Iron and Ammonia contents

Development of generalized feed forward network for predicting annual flood (depth) of a tropical river

The modeling of rainfall-runoff relationship in a watershed is very important in designing hydraulic structures, controlling flood and managing storm water. Artificial Neural Networks (ANNs) are known as having the ability to model nonlinear mechanisms. This study aimed at developing a Generalized Feed Forward (GFF) network model for predicting annual flood (depth) of Johor River in Peninsular Malaysia. In order to avoid over training, cross-validation technique was performed for optimizing the model. In addition, predictive uncertainty index was used to protect of over parameterization. The governing training algorithm was back propagation with momentum term and tangent hyperbolic types was used as transfer function for hidden and output layers. The results showed that the optimum architecture was derived by linear tangent hyperbolic transfer function for both hidden and output layers. The values of Nash and Sutcliffe (NS) and Root mean square error (RMSE) obtained 0.98 and 5.92 for the test period. Cross validation evaluation showed 9 process elements is adequate in hidden layer for optimum generalization by considering the predictive uncertainty index obtained (0.14) for test period which is acceptable

INFERENTIAL STATISTICS ASSESSMENT OF URBAN RAINFALL- RUNOFF MODELS

ABSTRACT Thorough understanding of the rainfall-runoff processes that influence watershed hydrological response is important and can be incorporated into the planning and management of water resources. This study assessed rainfallrunoff models through inferential statistics and benchmarked their runoff predictive accuracies against a proposed new runoff model. Linear regression model has been in use to model urban rainfall-runoff. However, the model was found to be statistically in-significant in this study. Hydrological implications from the regression model became in-consistent and obsolete. The 1954 simplified SCS runoff model was also statistical in-significant under two Null hypotheses rejection and paved way for the regional model calibration study. A new rainfall-runoff model was developed with calibration according to regional hydrological conditions. It out-performed simplified SCS runoff model and reduced RSS by 54%