Pusat Pengajian Kejuruteraan Mekanikal - Monograf

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Investigation of plasma pyrolysis gasifier for municipal solid waste
(2023-07-01)
Shatish Rao A/L Kaleswara Rao
This project focuses on the investigation of plasma pyrolysis gasifier for treatment of municipal solid waste (MSW). Plasma pyrolysis gasification is an advanced waste treatment technology that holds promise for efficient and sustainable management of municipal solid waste (MSW). The process involves subjecting MSW to high-temperature plasma generated by plasma electrodes, leading to the thermal decomposition of the waste into syngas and other valuable byproducts by incorporating steam. Synthesis gas, comprising hydrogen, carbon monoxide, and other combustible gases, can be utilized for energy generation, reducing reliance on fossil fuels and minimizing greenhouse gas emissions. The main advantages of plasma pyrolysis gasification for MSW is high conversion efficiency and the ability to handle diverse waste compositions. This project aims to investigate the plasma pyrolysis gasification for MSW and analyse the syngas produced from the decomposed MSW. To power the plasma electrodes, three pairs of 26kV,48mA transformers which can produce high voltage arc (more than 2000℃) is used, controlled by Solid State Relays (SSRs) in conjunction with an Arduino Uno microcontroller. The control system, comprising the Arduino Uno and SSRs, ensures precise and reliable regulation of the power supply to the plasma electrodes. Simulation of pyrolysis/gasification process has been done in Solidworks to study and analyses the heat transfer during the pyrolysis process. The experiment has been conducted several times in order to obtain the average results. The sample gas has been tested using gas chromatography in order to determine the syngas composition which is produced from the plasma pyrolysis gasification experiment. The experiment was conducted in two different ways where the feedstock feeding type is different. Method 1 is batch-to-batch feeding while method 2 is one-time feeding. Syngas was produced from both experiment type. The average hydrogen gas composition in volume for method 1 is 2.64% and for method 2 is 0.58%. The obtained syngas composition volume in this project is not sufficient enough to act as a fuel. Future works has been stated in order to improve the efficiency of overall pyrolysis/gasification process. A stirrer can be added in the chamber to allow all the MSW are exposed to the plasma arc.
Design and analysis of sonic scalpel
(2023-07-01)
Shahrezzat Bin Shahidan
The Ultrasonic scalpel is a widely employed medical instrument utilized in surgical procedures for the purpose of tissue incision and haemostasis. In this study, a new concept of Sonic scalpel was proposed through the idea of combining the thermal element (Kanthal A-1 Wire) and mechanical element (Coreless DC motor) as one complete system in order mimicking the functionality of Ultrasonic scalpel. The extent of lateral thermal spread exhibited by the prototype of the Sonic scalpel will be assessed in comparison to a commercially available coagulator pen in order to evaluate its functional capabilities. The development of the Sonic scalpel was designed in SolidWorks. After completing the fabrication of the Sonic Scalpel, a comprehensive evaluation was conducted on a chicken skin sample using the fully assembled system. The purpose was to establish the minimum threshold for cauterization and cutting under dynamic conditions, considering the influence of the mechanical component. The dissection site image captured through the Leica S6 E microscope was utilized for image processing in MATLAB software, aiming to enhance the clarity of thermal spread observation and enable precise measurements. The thermal element of the Sonic Scalpel, operating at a power of 16 W, demonstrated a minimum baseline temperature of 149°C, while the mechanical element operated at 0.37 W. The dissection process resulted in a 10 mm cut length, which took approximately 32 seconds. Following the dissection, the mean thermal spread on one side of the tissue was measured to be 1.068 mm for the Sonic Scalpel and 1.48 mm for the Commercial Coagulator Pen. These findings indicate that the Sonic Scalpel exhibited a lower degree of thermal diffusion within the tissue compared to the Commercial Coagulator Pen.
Study of pressure drop of dehumidifier under high relative humidity condition
(2023-07-01)
Samuel John Pitchay
Air conditioning systems dehumidify air using a lot of electrical energy and cost. An alternative method of removing humidity is to use desiccant dehumidifiers to remove moisture. An inherent problem with desiccant dehumidifiers is pressure drop due to the flow restriction. The objective of this study is to examine how much pressure is dropped based on the porosity of desiccant wheel and the desiccant material at high relative humidity. This experiment required the use of a wind tunnel experimental rig at the Heat Transfer Laboratory in the School of Mechanical Engineering, USM. The desiccant wheel was placed in the wind tunnel and the pressure drop was recorded. The outlet air velocity is key in understanding how the Reynolds number affects pressure drop. The correlation between Re and pressure can be seen by comparing them. For instance, desiccant clay with porosity, Φ = 0.9523 has a pressure drop of 55 Pa at Re = 21600. At Re = 28400, the pressure drop is 70 Pa. Meanwhile, for understanding how porosity affects pressure drop, the pressure drop can be seen for all porosities within a range of Re. For desiccant clay, with Re range of 21600 to 21700, the pressure drop at porosity, Φ = 0.9523 has a pressure drop of 55 Pa and for porosity, Φ = 0.6181, the pressure drop is 74 Pa. To summarize, as Re increases, the pressure drop increases and as porosity decreases, the pressure drop also increases.
Effect of speciment geometry on fracture toughness
(2023-07-01)
Safwan Bin Solihin
Fracture toughness is a quantitative property of the material. Fracture toughness measures the ability of a material containing a flaw to withstand an applied load. The most common method of measuring plain strain fracture toughness for metallic materials is standardized in the ASTM E399. However, it is widely acknowledged that the method is quite tedious. ASTM E1304 offers several advantages over the standard method of the ASTM E399. This research is, therefore, to develop and fabricate the Chevron-Notch plain strain fracture toughness testing system for metallic material according to ASTM E1304. The Chevron-Notch plain strain fracture toughness testing system was validated by determining the chevron-notch plane-strain fracture toughness of KIvM of austenitic steel SUS316 and ferritic steel AISI 1040 using Universal Testing Machine Instron 3367. By using this test, the plain-strain fracture toughness KQvM of austenitic steel SUS316 and ferritic steel AISI 1040 was defined. Before conducting the fracture toughness test, a tensile test was conducted, and the yield strength of the material was calculated. In this experiment, the digital image correlation, DIC was used to measure the displacement of the crack mouth opening displacement, CMOD. From the DIC displacement fields, the CMOD value as a function of load was successfully determined. The CMOD value increases when the applied load increases. However, the plain-strain chevron-notch fracture toughness, KIvM of SUS316 and AISI 1040 obtained in this study is considered invalid as the value of the width, Bcalculate is higher than the actual width, B value. The fracture toughness of the specimen is KQvM that we calculated is higher than the real fracture toughness. These finding results illustrate the chevron-notch test need to improve by more strategical dimensions to design the specimen and jig and create the methodological framework to develop a complex specimen
Controlling an inverted pendulum with microcontroller
(2023-07-01)
Raymond Roy A/L Rayappan
TWSB robot functions based on the principle of inverted pendulum. When a pendulum is hung with a mass below its pivot point is displaced to the left and right, will slowly return to its equilibrium position due to loss of energy to the surrounding and friction. When this configuration of pendulum is inverted and the rope is replaced with a solid rod, an inverted pendulum can be created. An inverted pendulum is a pendulum which has its center of mass above its pivot point where it is deemed unstable and will fall over without any additional support. This unstable system can be made stable by using a control system to monitor and control the angle of the solid rod through a closed-loop feedback system. This closed-loop feedback system must be able to monitor the angle of the rod continuously to avoid the pendulum from falling down. This project aims to study the performance and the ability of the Arduino microcontroller in controlling the TWSB robot and maintain an upright stable position throughout the experiment. Control system is very important for a TWSB robot to receive the data from the sensor and decide how much the robot has to move or tilt to stay in an upright stable position. The controller that is usually used for balancing purpose like in the case of the TWSB robot is PID controller. Simulation of TWSB robot has been done using Matlab software to study the performance of the PID controller in stabilizing the unstable TWSB robot. The model of the TWSB robot has been bulit using Matlab software in the Simscape Multibody before the simulation is done. The result from the simulation is later used during the experiment. The simulation is very important to be used during the experiment to get the desired result and so that the TWSB robot can be balanced in an upright and stable position. In this experiment, a TWSB robot is built with the PID gains of Kp=2.5 dan Kd=0.02. Based on the simulation result done in Simscape these values are good enough for the robot to balance. But when the experiment is done, the robot couldn’t balance itself properly and falls after few seconds. The TWSB robot also couldn’t move forward for a long time and falls down after moving a certain distance. The performance of the robot proved to be the same as the previous one and there seems to be no improvement in the performance of the TWSB robot.

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