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Shrimp culture is the fastest growing sector of the aquaculture industry in Malaysia. In culturing tiger prawn, the pH level needed for water is around 7.0-8.5. Currently, prawn farmer in Malaysia still using a manual method to control the water pH level by adding chemical (Lime), in which, the process required constant monitoring and control by labor. Since the prawns are so sensitive on pH level, an automatic pH control system is required to maintain the water pH automatically and precisely. This research was conducted to design a system that can control and provide feedback on the changes of pH level and been implemented at the reservoir tank that can act as water storage tank and prawn pond. Control system and pH sensor are the important components in controlling the pH level. Input from pH sensor was processed by controller. Moreover, after an error is detected by controller, the correction will be delivered to the system as a feedback process. Nitric acid with concentration of 0.001M was added to 25 liter water in tank 1 so that the pH level is decreased to pH 3.00. Different concentrations were used for slaked lime; 0.5M, 0.4M. 0.3M, 0.2M and 0.1M, to increase the pH from acid to slightly alkaline in the range of pH value 7.00-8.50. Slaked lime was pumped to Tank by water pump and it will stop if the pH level reaches the setting level. The time for the system to recover from pH 3.00 to 7.00-8.50 was recorded. The results shows that slaked lime with the concentration 0.5M has the fastest recover time which was 29s follow by 0.4M in 69s, 0.3M in 92s, 0.2M in 151s and 0.1M in 252s, respectively.

This study is about the development of a control system design using Programmable Logic Controller (PLC) system which gives food to the fish with a blower method. To perform fish feeding system automatically the control system will include PLC system, touch screen, emergency button, terminal block, speed controller, relay NY-2N, and power supply 240V. The component of the input systems are autonics sensor includes counter clockwise sensor, clockwise sensor and distance pulse sensor. While the components of the output systems are forward/reverse motor and blower. The overall system and its components are tested with the reliability test to check the components’ performance. The result of reliability system shows that all LED components emits light signal when both direct connection circuit and PLC system is interfaced. The feeding time need to be increased as the fish weight increased. Keywords: [PLC system, feeding rate, fish pond ]

Modelling of heat exchanger helps to define the error that occurs during the operation. Hence by optimizing it using genetic algorithm and particle swarm optimization, the error that occurred could be minimized and compared between both algorithms. The primary objective of this study was to obtain structural model using ARMAX equation. In this study, data from heat exchanger experiment was used to determine the parameter of ARMAX equation. Using genetic algorithm and particle swarm optimization, ARMAX parameters are optimized. Hence, the transfer function represents the plant for modelling. Validation test used were autocorrelation and cross-correlation to validate between normalised data input and error. Based on the result obtained, for GA, the input parameters are-0.000214, -0.000728, -0.0020, and-0.000804 while the output parameters are-1.0000, -0.1783, -0.1473 and 0.3248. For PSO, the input parameters are 0.0104, -0.0122, -0.0067 and 0.0118 while the output parameters are-0.4274, -0.1256, -0.1865 and-0.2614. From validation test, GA produced smoother and effective result compared to PSO with less noise exists.

Motorised cutter has been used in palm oil plantations and becomes an added value to improve its productivity during harvest. However, frequent use of the machine can cause damages to human hand arm and fingers caused by vibration. This paper presents a study on the hand arm vibration produced by a motorised cutter with pole 3 metres length. The objective of this study is to assess the safety of the machine to the users. The measurements involve taking vibration measurement at both grip of point 1 and point 2. These experiments involve two skilled users and two unskilled users which run in real palm oil plantation. The measurements are made according to ISO 5349,evaluation of hand arm was assessed from different angle of cutting, vibration values at both grip point and the standard limit exposure action A(8). Skilled user shows vibration exposed to less than 2.5m/s2 indicating safe condition of using the machine. The unskilled user shows vibration exposed to more than 2.5m/s2 indicating caution condition should be taken when handling the machine. From the data obtained, it is suggested to provide guidelines or training for any users so that less vibration transmission can be transferred to user when using this machine.