18 research outputs found
Replacing Self-Balancing System of Personal Transporter by Using Gyroscope
The methodology selected is by exploring various balancing system that are available in the market nowadays, and analyze those balancing system to establish design specification and criteria for this project system
Characterization of Palm Oil Ashes (POA) under Impulse
The characteristics of soils as used in earth electrode systems were investigated. In this project, the material proposed is palm oil ashes. The work involved particle size distribution, moisture holding capacity, compactness and also breakdown voltage under impulse. For particle size distribution, moisture holding capacity and compactness tests, it had been conducted in Geotechnic Lab, Faculty of Civil Engineering, UTM. The size chosen for every test in this project was 600μm and below. Meanwhile, for a breakdown under impulse test, it had been conducted in IVAT building, FKE. The particle chosen were 600μm because after the particle size distribution test, it is found, it covered 74% from the total of 300g POA. As for moisture holding capacity, it is found, that it can absorb 150% water referring to its dry mass. In the compaction test, the result shows that the optimum compacted are at 25% water added. As for the breakdown voltage impulse, it is found that the breakdown voltage of wet soils is always lower than the dry soils
Morus alba L. : creating miles of smiles / Nurhayati Mohamad Zain … [et al.]
The aims of the study are to determine the antimicrobial and antibiofilm activities of M. alba leaves extract against Streptococcus mutans (S.mutans). Method: The antimicrobial activity was evaluated using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The antibiofilm potential of extract was evaluated using biofilm inhibition assay and biofilm eradication assay. Oradex mouthwash with 0.12% CHX was used as a positive control. All experiments were performed in triplicate and repeated four times independently. Data were analysed using SPSS software version 23. A Kruskal-Wallis test followed by post-hoc Mann-Whitney U test was applied and level of significance was set at P < 0.001. Results: Morus alba (M.alba) leaves extract showed antimicrobial activity against S.mutans with MIC and MBC, 25mg/ml and 50mg/ml respectively. The adherence of bacteria on extract treated surface (0.5x MIC) was significantly reduced with adherence inhibition percentage of 72.5% compared to positive control CHX 0.12% (63%). At 0.5x MIC concentration, the extract also disrupted preformed biofilms with eradication percentage of 52.87%. Conclusion: The results suggest that M. alba leaves extract represents an untapped source of local plant with antibiofilm activity against S.mutans that could be a resource in the development of therapeutic natural products in managing dental caries
The differences in gender and education level on mental health literacy among youths in Malaysia
This quantitative study investigated mental health literacy (MHL) among Malaysian youth, considering gender and education level. A sample of 134 youths aged 15-30 from different regions in Malaysia participated, with 43 males and 91 females. Data were collected using a Google Form, assessing demographic background and MHL components. This study utilises random sampling as its sampling method. The assessment of mental health literacy was conducted using a formal standardised questionnaire. Data analysis was conducted using SPSS version 27, utilising descriptive statistics and one-way ANOVA. Results indicated no significant gender difference in MHL, but a significant relationship between education level and MHL. The study comprehensively examines how gender and education level influence mental health literacy among Malaysian youth, identifying challenges and disparities. Future research should explore socio-cultural influences and develop targeted interventions to improve mental health knowledge among youth with lower education levels. Policymakers and educators can use these findings to support the mental health needs of Malaysian youth, enhancing overall well-being
Effect of laser process loops on the hole diameter and hole formation of laser micro drilling on tc4
Laser micro drilling stands as a precise manufacturing method that employs a focused laser beam to craft accurate, small holes within a diverse array of materials. Its applications span across vital industries like aerospace, medical, and electronics, playing a pivotal role in creating components like fuel injectors, medical implants, and microelectronics. Within this context, a notable challenge emerges in obtaining a refined surface finish during laser micro drilling. This study delves into the impact of a laser loop, a crucial parameter, on the surface quality of TC4, also known as Ti6Al4V - an aerospace staple. Employing a Conventional Fiber Laser with a peak output of 30 W, the experiment meticulously directs the laser beam onto the TC4 surface via a microscope objective lens. The drilling process unfolds in controlled conditions, mitigating external variables such as temperature and humidity. Assessment of drilled hole surfaces transpires through both light and 3D microscopes. Interestingly, holes subjected to higher laser power and increased laser loop rates demonstrate enhanced surface smoothness. In essence, this inquiry demonstrates the substantial influence of laser loop on TC4's surface finish during laser micro drilling. Elevating the laser loop factor leads to heightened surface refinement and diminished roughness in drilled holes. It was found that the diameter entry of the micro-holes was increased by 61% - 89.35% and the diameter exit of the micro-holes also increased by 55.55% - 62.79%. The outcomes of this investigation offer valuable insights for refining the laser micro drilling process to achieve premium surface quality on TC4 and comparable materials. As such, these findings extend guidance for optimal laser loop settings in the realm of laser micro drilling across various materials, benefiting future manufacturing endeavors
Review of the Common Deposition Methods of Thin-Film Pentacene, Its Derivatives, and Their Performance
Pentacene is a well-known conjugated organic molecule with high mobility and a sensitive photo response. It is widely used in electronic devices, such as in organic thin-film transistors (OTFTs), organic light-emitting diodes (OLEDs), photodetectors, and smart sensors. With the development of flexible and wearable electronics, the deposition of good-quality pentacene films in large-scale organic electronics at the industrial level has drawn more research attention. Several methods are used to deposit pentacene thin films. The thermal evaporation technique is the most frequently used method for depositing thin films, as it has low contamination rates and a well-controlled deposition rate. Solution-processable methods such as spin coating, dip coating, and inkjet printing have also been widely studied because they enable large-scale deposition and low-cost fabrication of devices. This review summarizes the deposition principles and control parameters of each deposition method for pentacene and its derivatives. Each method is discussed in terms of experimentation and theory. Based on film quality and device performance, the review also provides a comparison of each method to provide recommendations for specific device applications
Effect of laser frequency and focal length on copper surface temperature during laser heating
Laser heating is a process that uses laser as a heat source. In this paper, the copper surface temperature during the laser heating process was studied by controlling the laser frequency and focal length. The laser heating experiment was conducted using a fiber laser marking machine and irradiated with a constant 27 W laser power within a duration of 51 s. The laser frequency and focal length were varied from 100 to 300 kHz and −3 cm to +3 cm, respectively. Meanwhile, laser surface modification (LSM) was performed on the copper rod surface to enhance the laser energy absorption. Furthermore, the defocusing modes for laser heating were used to analyze the variation of temperature. The focus point of the focal length for this experiment was set up at 18.4 cm from the focal plane and denoted as 0. Laser frequency and focal length were found to play an important role in increasing the surface temperature during laser heating since it affects the heat input delivered to the materials. It was found that the surface temperature reaches a higher degree, 879.2 °C with the combination of 200 kHz laser frequency at focal length
Elucidating on Time and Temperature Effects on Torrified Moldy Bread
Waste-to-energy is the preferred solution, according to the waste management hierarchy considering landfill waste disposal may not be the most effective method of waste usage. Torrefaction of kitchen waste to produce higher-quality solid fuels is an effective option with lower temperature requirements than pyrolysis and gasification. By addressing the problems, the fuel quality in terms of high heating value can be investigated. Also, the torrefaction parameters, temperature and time, can be examined on the fuel performance. The moldy bread undergoes torrefaction by torrefying it in the furnace with temperatures of 200, 250 and 300°C, respectively, with 15, 30, 45 and 60 mins of processing times. With increased torrefaction temperature, the mass dropped while the higher heating value (HHV) increased. The rise in carbon content also enhanced the torrefied moldy bread's fuel properties. Also, this is because the primary components of the moldy bread, particularly hemicellulose, have significantly decomposed. Therefore, processed temperature of 300°C at elevation time of 45 min produced tremendous gain than other parameters observed
Experimental Investigation of Thermal Fatigue Die Casting Dies by Using Response Surface Modelling
Mechanical and thermal sequences impact largely on thermo-mechanical fatigue of dies in a die casting operations. Innovative techniques to optimize the thermo-mechanical conditions of samples are major focus of researchers. This study investigates the typical thermal fatigue in die steel. Die surface initiation and crack propagation were stimulated by thermal and hardness gradients, acting on the contact surface layer. A design of experiments (DOE) was developed to analyze the effect of as-machined surface roughness and die casting parameters on thermal fatigue properties. The experimental data were assessed on a thermo-mechanical fatigue life assessment model, being assisted by response surface methodology (RSM). The eminent valuation was grounded on the crack length, hardness properties and surface roughness due to thermal fatigue. The results were analyzed using analysis of variance method. Parameter optimization was conducted using response surface methodology (RSM). Based on the model, the optimal results of 26.5 μm crack length, 3.114 μm surface roughness, and 306 HV0.5 hardness properties were produced
Thermally-Induced Crack Evaluation in H13 Tool Steel
This study reported the effect of thermal wear on cylindrical tool steel (AISI H13) under aluminum die-casting conditions. The AISIH13 steels were immersed in the molten aluminum alloy at 700 °C before water-quenching at room temperature. The process involved an alternating heating and cooling of each sample for a period of 24 s. The design of the immersion test apparatus stylistically simulated aluminum alloy dies casting conditions. The testing phase was performed at 1850, 3000, and 5000 cycles. The samples were subjected to visual inspection after each phase of testing, before being examined for metallographic studies, surface crack measurement, and hardness characteristics. Furthermore, the samples were segmented and examined under optical and Scanning Electron Microscopy (SEM). The areas around the crack zones were additionally examined under Energy Dispersive X-ray Spectroscopy (EDXS). The crack’s maximum length and Vickers hardness profiles were obtained; and from the metallographic study, an increase in the number of cycles during the testing phase resulted in an increase in the surface crack formation; suggesting an increase in the thermal stress at higher cycle numbers. The crack length of Region I (spherically shaped) was about 47 to 127 µm, with a high oxygen content that was analyzed within 140 µm from the surface of the sample. At 700 °C, there is a formation of aluminum oxides, which was in contact with the surface of the H13 sample. These stresses propagate the thermal wear crack length into the tool material of spherically shaped Region I and cylindrically shape Region II, while hardness parameters presented a different observation. The crack length of Region I was about 32% higher than the crack length of Region II