Papers by Mohd Zaki Nuawi
Materials
Considerable research has been conducted in the past decade and a half regarding the bio-lubrican... more Considerable research has been conducted in the past decade and a half regarding the bio-lubricants potential to replace mineral-based lubricants as mainstream lubricants such as engine oil, hydraulic oil, compressor oil, and metalworking oil. This study studied several bio-lubricants (rapeseed oil, palm olein, and soybean oil) and a mineral-based lubricant, SAE40. The bio-lubricants have better physiochemical, tribological characteristics and environmental friendly nature, and are promising to replace mineral-based lubricants. In this study, a journal bearing test rig (JBTR) was developed in order to investigate the effect of journal speed on the temperature of oil film with time. Additionally, the load-carrying capacity of bio-oils was tested against the mineral-based lubricant SAE40 by adding a load on the journal. For all three speeds, i.e., 1000, 1500, and 2000 rpm, the bio-lubricants recorded minimum temperature. At 1000 rpm, rapeseed oil recorded a 9.2% lower temperature than...
TELKOMNIKA (Telecommunication Computing Electronics and Control), 2021
Preprogrammed monitoring of engine failure due to spark plug misfire can be traced using a method... more Preprogrammed monitoring of engine failure due to spark plug misfire can be traced using a method called machine learning. Unluckily, a challenge to get a high-efficiency rate because of a massive volume of training data is required. During the study, these failure-generated were enhanced with a novel statistical signal-based analysis called Z-freq to improve the exploration. This study is an exploration of the time and frequency content attained from the engine after it goes under a specific situation. Throughout the trial, the misfire was formed by cutting the voltage supplied to simulate the actual outcome of the worn-out spark plug. The failure produced by fault signals from the spark plug misfire were collected using great sensitivity, space-saving and a robust piezo-based sensor named accelerometer. The achieved result and analysis indicated a significant pattern in the coefficient value and scattering of Z-freq data for spark plug misfire. Lastly, the simulation and experimen...
The objective of this study is to determine the thermal comfort among worker at Malaysian automot... more The objective of this study is to determine the thermal comfort among worker at Malaysian automotive industry. One critical manual assembly workstation had been chosen as a subject for the study. The human subjects for the study constitute operators at Body Assembly Station of the factory. The environment examined was the Relative Humidity (%), Airflow (m/s), Air Temperature (°C) and Radiant Temperature (°C) of the surrounding workstation area. The environmental factors were measured using Babuc apparatus, which is capable to measure simultaneously those mentioned environmental factors. The time series data of fluctuating level of factors were plotted to identify the significant changes of factors. Then thermal comfort of the workers were assessed by using ISO Standard 7730 Thermal sensation scale by using Predicted Mean Vote (PMV). Further Predicted percentage dissatisfied (PPD) is used to estimate the thermal comfort satisfaction of the occupant. Finally the PPD versus PMV were pl...
JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES, 2017
The best feature scheme is vital in musical instrument sound clustering and classification, as it... more The best feature scheme is vital in musical instrument sound clustering and classification, as it is an input and feed towards the pattern recognition technique. This paper studies the relationship of every traditional Malay musical instrument acoustic sounds by implementing a correlation and clustering method through the selected features. Two types of musical instruments are proposed, namely flutes involving key C and key G classes and caklempong consisting of gereteh and saua. Each of them is represented with a set of music notes. The acoustic music recording process is conducted using a developed design experiment that consists of a microphone, power module and data acquisition system. An alternative statistical analysis method, namely the Integrated Kurtosis-based Algorithm for Z-notch Filter (I-kaz TM), denoted by the I-kaz coefficient, Z ∞ , has been applied and the standard deviation is calculated from the recorded music notes signal to investigate and extract the signal's features. Correlation and clustering is done by interpreting the data through Z ∞ and the standard deviation in the regression analysis and data mining. The results revealed that a difference wave pattern is formed for a difference instrument on the time-frequency domain but remains unclear, thus correlation and clusterisation are needed to classify them. The correlation of determination, R 2 ranging from 0.9291 to 0.9831, thus shows a high dependency and strong statistical relationship between them. The classification of flute and caklempong through mapping and clustering is successfully built with each of them separated with their own region area without overlapping, with statistical coefficients ranging from (2.
World applied sciences journal, 2011
their response using two types of synthetic signals, TSA and TSB. The optimized order of I-kaz Mu... more their response using two types of synthetic signals, TSA and TSB. The optimized order of I-kaz Multi Level coefficient was chosen base on the sensitiveness of the coefficient response with respect to the changes of amplitude in TSA and frequency in TSB synthetic signals. This study indicated that the response of all orders of I-kaz Multi Level coefficients showed an increasing trend with respect to the increment in amplitude and frequency of TSA and TSB signals respectively. The 6 order of I-kaz coefficient, Z was the most efficient th 6
This study will utilize the TRIZ approach for designing an innovative integrated rotating dynamom... more This study will utilize the TRIZ approach for designing an innovative integrated rotating dynamometer (IRD). This innovative IRD is designed, constructed and fabricated for fulfilment the need of measuring the cutting force in a wireless environment system. A complete data conditioning system was incorporated into a modified tool holder in order to collect and transmit the cutting force signal to the data acquisition system. The rotating dynamometer has been subjected to a series of tests to determine its static and dynamic characteristics. The results show that the integrated rotating dynamometer and tool holder can reliably measure the cutting force in milling and drilling processes.
Modal Analysis is a common practice to define parameters of structure under scientific view. The ... more Modal Analysis is a common practice to define parameters of structure under scientific view. The properties that come along need to be enlightened so that every circumstance appeared may be tackled in proper manner. Experimental Modal Analysis (EMA) is a well-known procedure for determining modal parameters. The EMA is regarded as an ‘indoor tools’ to examine modal parameters. Meanwhile, Operational Modal Analysis (OMA) on the other hand acts as an ‘outdoor tools’, or operated at site. Here, the EMA analysis method will be discussed. Modal parameters consist of mode shape, natural frequency and damping ratio.
ARPN journal of engineering and applied sciences, 2018
Tool failure is a major and undesirable occurrence affecting the overall operating cost and time ... more Tool failure is a major and undesirable occurrence affecting the overall operating cost and time as the machining needs to be done once again to fix the mistake. Therefore, this paper introduced an efficient and inexpensive way to overcome the problem by developing tool wear monitoring system using Macro-Fibre Composite (MFC) sensor via alternative statistical signal analysis method, namely Integrated Kurtosis-based Algorithm for Z-notch filter (I-kaz TM ). A piece of MFC sensor amplified by a power module was mounted on a tool holder in the turning machine to capture vibration signal data using data-logger while cutting the workpiece. The operation ran continuously until criteria of 0.3 mm tool wear achieved with the help of a microscope for wear measurement. The machining was set at 250 and 300 m/min of cutting speeds, while the feed and depth of cut were kept constant at 0.25 mm/rev and 0.12 mm respectively. The raw data were then extracted and observed in time and frequency doma...
An alternative advanced statistical analysis method known as the I-kaz 4D or I-kaz 4 channels whi... more An alternative advanced statistical analysis method known as the I-kaz 4D or I-kaz 4 channels which using the sensor fusion concept by applying four sensors to collect the vibration signals that excited by the impact hammer was introduced in this study. The study carried for copper (Cu). The specimens were in shape of circular, rectangular and square. The impact force were set with the range of different forces. The four piezofilm sensors been placed at specimen’s surface to observe and record the vibration signal after the impact. The obtained results been compared with the results obtained by I-kaz 4D method.
Jurnal Teknologi, 2016
Fatigue is a gradual process related with an effort to keep awake, eventually resulting in declin... more Fatigue is a gradual process related with an effort to keep awake, eventually resulting in declination of human performance. It is one of the well-known risk factors for traffic accidents. The objective of this study is to understand the psychophysiological aspects of driver fatigue by using driving simulator. This study had focused on heart rate (HR) measures to determine drivers’ performance as this method can be measured in a less intrusive manner. Hence, in this study, 17 relevant studies were discussed, chosen from electronic databases. This study encompasses a range of subject areas, including concepts and theories of fatigue, driver fatigue, and psychophysiological indicators and countermeasures of driver fatigue. A variety of psychophysiological measures and parameters have been used in past research as indicators of fatigue. Based on this review, HR can assists researchers to determine performance according to a task demand, condition and its complexity. The review highlig...
Frattura ed Integrità Strutturale, 2018
This paper presents the behaviour of fatigue damage extraction in fatigue strain histories of aut... more This paper presents the behaviour of fatigue damage extraction in fatigue strain histories of automotive components using the probabilistic approach. This is a consideration for the evaluation of fatigue damage extraction in automotive components under service loading that is vital in a reliability analysis. For the purpose of research work, two strain signals data are collected from a car coil spring during a road test. The fatigue strain signals are then extracted using the wavelet transform in order to extract the high amplitude segments that contribute to the fatigue damage. At this stage, the low amplitude segments are removed because of their minimal contribution to the fatigue damage. The fatigue damage based on all extracted segments is calculated using some significant strain-life models. Subsequently, the statistics-based Weibull distribution is applied to evaluate the fatigue damage extraction. It has been found that about 70% of the probability of failure occurs in the 1.0 x 10-5 to 1.0 x 10-4 damage range for both signals, while 90% of the probability of failure occurs in the 1.0 x 10-4 to 1.0 x 10-3 damage range. Lastly, it is suggested that the fatigue damage can be determined by the Weibull distribution analysis KEYWORDS.
Micromachines, 2017
This study presents the creation of a Karman vortex for a fluttering electromagnetic energy harve... more This study presents the creation of a Karman vortex for a fluttering electromagnetic energy harvester device using a cylinder. The effects of two parameters, which are the diameter and the position of the cylinder, were investigated on the Karman vortex profile and the amplitude of the fluttering belt, respectively. A simulation was conducted to determine the effect of the creation of the Karman vortex, and an experiment was performed to identify influence of the position of the cylinder on the fluttering belt amplitude. The results demonstrated that vortex-induced vibration occurred at the frequency of the first natural mode for the belt at 3 cm and 10 cm for the diameter and position of the cylinder, respectively. Under such configuration, an electromagnetic energy harvester was attached and vibrated via the fluttering belt inside the turbulent boundary layers. This vibration provides a measured output voltage and can be used in wireless sensors.
JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES, 2016
This paper presents the effect of temperature on the fatigue life behaviour of aluminium alloy AA... more This paper presents the effect of temperature on the fatigue life behaviour of aluminium alloy AA6061, under constant loading conditions, by using an analytical approach. Most of the moving components in automotive engines are under the combined effects of fatigue and temperature. Fatigue life predictions by using conventional experimental methods take a significantly long time. The finite element analysis (FEA) was used for the prediction of fatigue life and point for fatigue failure in the aluminium alloy AA6061 specimen. The stress-life curves at different levels of elevated temperature (50, 100, 150, 200, 250, and 300℃) were predicted by using a mathematical approach of linear interpolation. The maximum temperature of 300℃ was chosen based on the extreme temperature on a piston face that can be reached during the operation of the engine. The results for fatigue life at ambient temperature and at elevated temperature were compared by the Basquin relation and a decrease of 99% in fatigue life cycles was found at 300℃. A general mathematical expression was obtained to calculate the fatigue life for aluminium alloy, AA6061, at elevated temperatures. Therefore, it was concluded that the mathematical expression used in this study can be used as a good alternative approach for time consuming experimental methods. Hence, the mathematical expression proposed in this paper can be used for the early prediction of fatigue life at elevated temperatures without using much experimental analysis.
IOP Conference Series: Materials Science and Engineering, 2016
Flapping wing in tandem configuration may offer enhanced aerodynamic performance at low Reynolds ... more Flapping wing in tandem configuration may offer enhanced aerodynamic performance at low Reynolds number, in which micro air vehicles operate. The present study aims to investigate the effect of fore-hind wing pitch difference on the aerodynamic performance of tandem wings. To that end, two-dimensional, laminar flow around two thin flat airfoils that are sinusoidally plunging in phase with each other, were computationally simulated at a Reynolds number of 10000, using a flow solver in an Arbitrary Lagrangian-Eulerian framework. The fore wing pitch angle was fixed to 10 • , while the hind wing pitch angle was varied between −10 • , 0 • , 10 • and 20 •. Numerical results shows that aerodynamic performance of the fore wing may be affected by the hind wing pitch angle and that tandem wings may offer improved lift to drag efficiency at some optimal fore-hind wing pitch difference compared to twice the results of a similar single wing case. In addition, the complex fore-hind wing vortex interaction is also affected by the hind wing pitch angle.
Pressacademia, 2017
In ergonomics perspective, car seat is defined as one of the main workstation when the driver is ... more In ergonomics perspective, car seat is defined as one of the main workstation when the driver is performing driving task. The car seat itself provides support and space for the driver over the head, at the upper and lower back, at the buttock and also at the thigh. There has been abundant research regarding car seat in the past decades. However, in spite of vast studies on this issue, limited studies were found on sitting effect to the pressure when adopting different driving position. Hence, this study integrates objective and subjective evaluation to predict pressure felt level. Mapping of the pressures distribution was taken to the seat pan. This study is a static field experiment where data acquired are in the quantitative form. Findings show that the pressure of the heavier subject is more scattered at the buttock area, while the lighter subject has mild stress concentrated under ischium tuberosity.
International Journal on Advanced Science, Engineering and Information Technology, 2017
This paper discusses the development method to determine the accuracy of pronunciation of the wor... more This paper discusses the development method to determine the accuracy of pronunciation of the word using global statistical signal analysis parameters. An engineering word that has been chosen is 'leaching'. The pronunciation of the word 'leaching' in the French language has been recorded from 1 native speaker and 4 students. The recording processes use a microphone-laptop system configuration and the signal analyzing processes use MATLAB software. Time and frequency domain plots show a variety of waveforms according to the recorded pronunciation. For data processing, statistical signal analysis parameters involved to extract the signal's features are kurtosis, root mean square and skewness. The mapping process has been performed to cluster each data. The position of the samples from the students is referred to the samples from the native speaker. The result of the accuracy of the pronunciation of words for each student can be evaluated through the comparison of the position of all the samples. In conclusion, the development of mapping and clustering methods are able to characterize the accuracy of the pronunciation of words.
Jurnal Kejuruteraan, 2016
This paper proposes an implementation of alternative statistical signal analysis method in charac... more This paper proposes an implementation of alternative statistical signal analysis method in characterising material properties of polymer using impulse excitation technique (IET) in accordance with ASTM E1876 standard. Five types of cylindrical shape polymer specimens are used, namely acrylics (AC), poly vinyl chloride (PVC), polyethylene (PE), cast nylon (MC), and polyoxymethylene (POM). Experimental procedure is done based on non-destructive testing (NDT) concept by tapping the specimens using an impact hammer within a specific range of impact force, while accelerometer sensor Endevco 751-100 is used to detect the vibration produced. The detected vibration and the impact force signal which is triggered by impact hammer are captured using NI 9234 data acquisition device and computer. The signal is interpreted and statistically analysed using Mesokurtosis Zonal Non-parametric (M-Z-N) analysis method. As a result, mathematical model equations for determining two material properties which are tensile strength and thermal conductivity have been successfully developed. They are derived through correlation between the signal data and M-Z-N coefficient. Verification of the equation is done and the calculated errors to be in the range of 5.55% to 9.74%. Hence, this proves that the correlation can be used as a standard for determining these material properties through M-Z-N method, which is efficient and low cost.
Dynamic fracture properties of most engineering materials are generally assessed using the charpy... more Dynamic fracture properties of most engineering materials are generally assessed using the charpy test. The dynamic responses of the standard charpy impact machine are studied by running experiments using strain gauges and a specific data acquisition system in order to obtain the impact response and for this reason, the numerical analysis by means of the finite element method has been used to obtain the findings. In addition, the non-linear dynamic finite element is used for simulating the charpy impact test. The charpy test modelling was used in order to obtain the strain on the striker during the test. Two different velocities (5.18 m/s and 3.35 m/s) which are similar to the instrument charpy impact machine with the standard charpy modelling from the aluminium 6061 and low carbon steel 1050 as the rim material were used. A power spectrum density (PSD) is used to convert a signal from the time domain to the frequency domain using the fast Fourier transform (FFT) method. Related par...
This paper presents scattering of fatigue time series data to develop a relationship between the ... more This paper presents scattering of fatigue time series data to develop a relationship between the fatigue damage and the Morlet wavelet coefficient. In order to achieve the purpose, the SAESUS strain signal was inputted into a segmentation algorithm based on the wavelet coefficient amplitude level which produces 49 segments that each has an overall fatigue damage. Observation of the fatigue damage and the wavelet coefficient was made on each segment. In the end of process, this algorithm produced a more reliable and suitable method of fatigue stain signal segmentation and segment by segment analysis to identify any improvements in the data scattering for fatigue data clustering prospects. Scatter plot was produced based on the relationship between segmental fatigue damage and its corresponding wavelet coefficient value. As the result, the relationship between the fatigue damage and the Morlet wavelet coefficient is strong and parallel, since the higher wavelet coefficient presents the higher fatigue damage, otherwise, it is the lower fatigue damage.
This paper discusses the fatigue strain signal behaviour of different road surface conditions and... more This paper discusses the fatigue strain signal behaviour of different road surface conditions and its relationship to the fatigue damage of an engine mount bracket. Two different sets of fatigue strain signals were obtained from an engine mount bracket of an automobile: when the automobile was driven on a highway surface and on a residential area road surface. The behaviour of the strain signal was then analysed and classified using both statistical and signal processing tools. Damage values as a result of the corresponding fatigue strain signals also determined using commercial finite element software. The fatigue strain signal behaviour was influenced by the road surface conditions, which affected the damage to the engine mount bracket. The integrated kurtosis-based algorithm for the Z-filter and power spectral density calculation were found to be the most suitable signal analysis approaches to correlate the fatigue strain signal behaviour with the engine mount bracket damage.
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Papers by Mohd Zaki Nuawi