Hand-arm vibration disorder among grass-cutter workers in Malaysia

Prolonged exposure to hand-transmitted vibration from grass-cutting machines has been associated with increasing occurrences of symptoms and signs of occupational diseases related to hand-arm vibration syndrome (HAVS). Methods. A cross-sectional study was carried out using an adopted HAVS questionnaire on hand-arm vibration exposure and symptoms distributed to 168 male workers from the grass and turf maintenance industry who use hand-held grass-cutting machines as part of their work. The prevalence ratio and symptom correlation to HAVS between high and low–moderate exposure risk groups were evaluated. Results. There were positive HAVS symptoms relationships between the low–moderate exposure group and the high exposure group among hand-held grass-cutting workers. The prevalence ratio was considered high because there were indicators that fingers turned white and felt numb, 3.63, 95% CI [1.41, 9.39] and 4.24, 95% CI [2.18, 8.27], respectively. Less than 14.3% of workers stated that they were aware of the occupational hand-arm vibration, and it seemed to be related to the finger blanching and numbness. Conclusion. The results suggest that HAVS is under-diagnosed in Malaysia, especially in the agricultural sectors. More information related to safety and health awareness programmes for HAVS exposure is required among hand-held grass-cutting workers

Octave band technique for noise measurement at the source, path, and receiver of gas turbines in oil and gas facilities

Noise measurement is essential for industrial usage. However, further attention to preventing noise pollution is needed, especially when working with equipment generating a high noise level, such as gas turbines. This study aims to determine the best way to perform noise measurement and analyze the octave band frequency generated by noise pollution caused by gas turbine equipment. Data from site measurements show that the gas turbines produce more than 85 dB of noise with a Z-weighted measurement. A noise measuring investigation was conducted to obtain the data for the 1/3 octave band. A frequency-domain was used to comprehend the properties of the noise measurement frequency band. The frequency band was classified into three different zones called low, medium, and high frequency, which is useful in noise measurement analysis to identify a viable solution to reduce the noise. On�site sampling was performed at the source, path, and receiver of three separate gas turbine locations within oil and gas operations. The 1/3 octave band data collection results at the sound source, path, and receiver demonstrate the noise level distribution at the perimeter of gas turbine installations in the low and medium frequency ranges. Most of the high noise frequency range is between 250 Hz and 2 kHz for source, path, and receiver. All acquired values are compared to the Department of Safety and Health (Occupational Safety and Health (Noise Exposure) Regulations 2019 in Malaysia. As a result, oil and gas service operators can monitor and take countermeasures to limit noise exposure at oil and gas facilities

Prediction on hand arm vibration exposure cause-effect among grass-cutting workers in Malaysia

Prolonged exposures to hand-transmitted vibrations from grass-cutting machines have been associated with increasing occurrences of signs of occupational diseases related to the hand-arm vibration syndrome (HAVS). However, there are no specific processes available that cover the subjective and objective health cause-effects of the hand arm vibration risk factors during onsite operations. The objectives are (1) to measure the health subjective and objective risks during normal working conditions among hand-held grass-cutting workers and (2) to determine the significant correlation of the subjective and objective measurement variables of the Hand Arm Vibration Exposure Risk Assessment (HAVERA) on hand arm vibration symptoms and disorders. The study was conducted in two stages: evaluation of the HAVERA variables and development of the health prediction cause-effect model of the HAVERA process using multiple linear regressions and feed forward neural network programming. In the onsite measurement, the daily vibration value depicted an exceeded exposure action value of 2.5 m/s2 for both hands; and experiences of any finger colour change were claimed by 80% of the 204 subjects. This shows that HAVERA process provided a good indication of HAVS which are reported as vascular, neurological and musculoskeletal disorders. In the right and left hand prediction model development, the results demonstrated a higher reliability performance as compared to the linear model for hand grip strength and hand numerical scoring assessment. The prediction of the HAVERA model using the neural network method has been developed for monitoring health conditions due to hand-transmitted vibrations among hand-held grasscutting workers in Malaysia

Measurement of CO, CO2, Particulate Matter (PM10), Cockpit and Ambient Temperature, Humidity and Noise Level at UTHM Hangar

This study is focussed on works that are done at the hangar and its effect on human health. The absence of proper air quality or noise level study at the current UTHM hangar has inspired to conduct this study. The objective of this study is to measure the emission rate of carbon monoxide (CO), carbon dioxide (CO2), particulate matter (PM10), and measure the cockpit temperature, ambient temperature, humidity, and noise level of PT6A-20 engine to obtain the data at the Universiti Tun Hussein Onn Malaysia (UTHM) Hangar. There are presence of 2 engines which are Lycoming O-360 and turboprop PT6A-20 at the hangar. Lycoming O-360 uses avgas and turboprop PT6A-20 uses jetA1 fuel type which will produce higher rate of emission and that is the reason of PT6A-20 engine being chosen. So this study aims to highlight a comprehensive data of CO, CO2, particulate matter (PM10), cockpit and ambient temperature, humidity and noise level regarding the turboprop PT6A-20 engine at hangar of UTHM to aid future researchers and ensure the air quality and safety rules of the hangar. The air quality standards are used as guideline are the Malaysia Ambient Air Quality Standard and Indoor Air Quality Standard based on the Department of Occupational Safety and Health (DOSH). Also, Occupational Safety and Health (Noise Exposure) Regulations 2019 is used as the standard for noise level. Q-Trak Plus IAQ Monitor model 8554 is used to measure the emission rate of CO,CO2, level of humidity and cockpit temperature. Dust Trak Aerosol Monitor is used to measure the emission rate of PM10, Pico Data Logger is used to measure the ambient temperature and finally 1352H integrating sound level meter was used to measure the noise level of PT6A-20 engine. Based on the results produced, only carbon monoxide and carbon dioxide are below than the safety limit. The othe 5 parameters which are PM10, cockpit and ambient temperature, humidity and noise level are above the allowable limit according to DOSH

Materials selection analysis for vibration isolator pads

Isolator pads which also called as vibration pads are used in many applications to isolate vibration, extend machine life, reduce maintenance costs and reduce excessive wear. It is the process of isolating objects such as equipment from harmful vibration sources. In this study, two types of isolator pad materials; neoprene and sorbothone were analyzed in order to be used for stackable washing and dryer machine. In this case, the stackable washing and dryer machine together with the isolator pads were simplified into two degree of freedom system, where the first and the second natural frequencies for each material of isolator pad were determined by using matrix iteration method, in which later were validated by a modern tool such as Matlab. For neoprene material, the first natural frequency obtained was 44.2 rad/s and the second natural frequency is 107.7 rad/s. By contrast, sorbothone material shows slightly higher for both first and second natural frequencies compared to neoprene, which were 57.9 rad/s and 141.0 rad/s respectively. From this result, it shows that neoprene is suitable to be used as the coupling (spring) material since it has lower natural frequency value compared to sorbothone, besides the second natural frequency of sorbothone material is near to the forcing frequency 140 rad/s, thus could amplified the vibration due to resonance

Modelling of rigid walled enclosure couple to a flexible wall using matlab and ansys APDL

Generally, solutions to improve the noise problems in enclosure are to redesign or modifying the system such as increasing the thickness of the wall panels, enhancing the elasticity of the structure, and increase the damping mechanism of the wall structure. In this paper, the application of vibroacoustic modelling of enclosure coupled to a flexible wall was presented. The sound pressure characteristics of rigid walled enclosure, such as natural frequency and mode shape were determined using two approaches which are finite element simulation of Ansys® and mathematical model. The mathematical equations derived in Matlab® such as rigid walled enclosure and rigid walled enclosure coupled to flexible wall were used to validate finite element analysis (FEA). The result indicates that the theory and FEA display in a good agreement. Thus, proved that the FE model was accurate and can be applied in further research such as sound pressure and noise attenuation in enclosure

Prevalence and impact of work-related musculoskeletal disorders among food delivery riders in Eastern Peninsular Malaysia

Work-related Musculoskeletal Disorders (WMSDs) are currently a matter of concern in the occupational world, where it is the leading cause of disability among workers. Food delivery riders were among the neglected workers even though they were highly exposed to the WMSDs. Thus, this study aims to quantify the magnitude of WMSDs among the riders and the impact on their work. This was a cross-sectional study involving 191 food delivery riders in Eastern Peninsular Malaysia. The Standardized Nordic Musculoskeletal Questionnaire (M-SNMQ), which was self-administered and validated for Malay translation, was used to quantify the prevalence of WMSDS based on various specific body regions. WMSD prevalence over a 12-month period was 74.9%. Upper back pain (UBP) (55.6%) and lower back pain (LBP) (73.3%) were the two most common body regions to experience WMSD symptoms. The least-complained body regions were thighs and feet, with a prevalence of 2.6% and 3.1%, respectively. The affected body regions that caused the highest daily life disturbance were the shoulders and knees, while those with shoulders symptom were more likely to be absent from work. Finally, LBP was the highest body region with at least a moderate pain score. In general, the findings should be a matter of concern among health authorities and others to improve the quality of life among the riders. To lower the prevalence of WMSDs among this understudied group, additional interventional research should be built on the findings of this study