Pusat Pengajian Kejuruteraan Mekanikal - Monograf
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- PublicationDesign and analysis of thermomechanical cautery system(2022-07-24)Aina Shafiqah binti Shamsul MaarifThe cauterization process is a method for heating a portion of tissue to close the wound and mitigate the bleeding by tissue coagulation prior to the tissue’s cutting. In this study, a new concept of Thermomechanical Cautery was proposed through the idea of combining the thermal element (Kanthal A-1 Wire) and mechanical element (DC Motor) as one complete system. Thermal cautery and Ultrasonic cautery are commercially used for the surgery for tissue cutting and hemostasis. The lateral thermal spread across these 3 cautery devices was compared. The development of the Thermomechanical Cautery was designed in SolidWorks, followed by the Finite Element Analysis in ANSYS Workbench. A thermal element was first tested on the chicken skin sample to determine its minimum baseline for cauterization and cutting in a static condition. Once the fabrication of the Thermomechanical Cautery is done, a testing with the complete system was carried out in a dynamic manner due to the presence of the mechanical element. By using light microscopy, the image of the dissection site was captured, and the image will undergo an image processing technique in MATLAB to measure its lateral thermal spread. The minimum baseline for cauterization and dissection is 180.1°C with power supply of 10.96 W for the thermal element and 0.69 W for the mechanical element. It took about 30 seconds for a 10 mm cut length. After the dissection, the mean of the thermal spread on one side for Themomechanical Cautery, existing Thermal Cautery and Ultrasonic Cautery were 0.712 mm, 1.436 mm and 1 mm, respectively. Thus, the Thermomechanical Cautery recorded the lesser degree of thermal spread in tissue.
- PublicationInvestigation of plasma pyrolysis gasifier for municipal solid waste(2023-07-01)Shatish Rao A/L Kaleswara RaoThis 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.
- PublicationDesign and analysis of sonic scalpel(2023-07-01)Shahrezzat Bin ShahidanThe 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.
- PublicationStudy of pressure drop of dehumidifier under high relative humidity condition(2023-07-01)Samuel John PitchayAir 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.
- PublicationEffect of speciment geometry on fracture toughness(2023-07-01)Safwan Bin SolihinFracture 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