Zakri Ghazalli

Purpose: Environmental problems in manufacturing industries are a global issue owing to severe lack fossil resources. In assembly sequence planning (ASP), the research effort mainly aims to improve profit and human-related factors, but it still lacks in the consideration of the environmental issue. This paper aims to present an energy-efficient model for the ASP problem. Design/methodology/approach: The proposed model considered energy utilization during the assembly process, particularly idle energy utilization. The problem was then optimized using moth flame optimization (MFO) and compared with well-established algorithms such as genetic algorithm (GA), particle swarm optimization (PSO) and ant colony optimization (ACO). A computational test was conducted using five assembly problems ranging from 12 to 40 components. Findings: The results of the computational experiments indicated that the proposed model was capable of generating an energy-efficient assembly sequence. At the same time, the results also showed that MFO consistently performed better in terms of the best and mean fitness, with acceptable computational time. Originality/value: This paper proposed a new energy-efficient ASP model that can be a guideline to design assembly station. Furthermore, this is the first attempt to implement MFO for the ASP problem.

The use of metallic biomaterials for replacement of biomedical implants has been traced back from the nineteenth century. These metallic biomaterials have been declared as clinical success as their mechanical properties that satisfy the prerequisite of the human bone. Nevertheless, critical issues of the materials when they are utilised as implants; including the releasing toxic and harmful metal ions through wear and corrosion processes after longer implantation. Besides that, the bonding strength between bone and implants itself is considered weak due to the different components of human bone and metal implants. Hence, developing hydroxyapatite (HAp) coating on metallic biomaterials is expected to overcome the problems faced by biocompatible metallic biomaterials. As far as this, various commercial techniques have been introduced to develop the HAp coating on metallic biomaterials. The techniques are including plasma-spraying method, sol-gel dip-coating, electrochemical deposition and high-velocity suspension plasma-spraying. The formation of HAp coating on metallic biomaterials improved the corrosion resistance together promoting its load-bearing ability and enhanced substrate-coating adhesion.

Musculoskeletal discomfort (MSD) is very common condition in automotive industry. MSD is affecting the worker's health, well-being and lower down the productivity. Therefore, the main objective of this study was to identify the prevalence of MSD and ergonomics risk factors among the production team members at a selected automotive component manufacturer in Malaysia. MSD data were collected by conducting structure interview with all participants by referring to the Cornell Musculoskeletal Disorder Questionnaire (CMDQ). Those production team members who achieved a total discomfort score for all body regions more than 100 was selected for job task assessment. The physical exposure risk factors of work related musculoskeletal disorders (WMSD) has evaluated by using Quick Exposure Check (QEC) techniques. The results of the study identified the severe MSD associated with production assembly team members. It is expected that the prevalence of MSD for those production assembly team members was lower back (75.4%), upper back (63.2%), right shoulder (61.4%), and right wrist (60%). The QEC analysis discovered that about 70% of job tasks had very high risks for neck posture and 60% had high risks for the back (in moving condition) and shoulder/arm postures. There were 80% of respondents have produced a high score for exposure risk to vibration. As a conclusion, the main implication of the current study is that special attention should be paid to the physical and psychosocial aspects in production team members with musculoskeletal discomfort to improve their safety, health, and well-being, maintain work ability and productivity.

Human range of motion (ROM) is a measurement of human movement capability in the kinesiology study. To measure ROM a device known as goniometer is used specifically in the joint angle measurement. However, the current measurement is manually measured in static condition was performed by the traditional goniometer device which operated in an analog scale. Therefore, the objective of this project is to develop a wearable electronic goniometer that integrates with Arduino microcontroller that sense and record the motion of patient’s knee wirelessly. Device will display the motion of knee joint angle through Android mobile phone via Bluetooth module either in static or in dynamic conditions. In this case, potentiometer will act as a rotation sensor by interpreting the analog data obtained by Arduino. The potentiometer is attached to patient’s leg will measure the knee joint angle as potentiometer rotated. The knee flexion angle was selected for analyses due to the importance of identifying the knee osteoarthritis problem in the lower extremities. In fact an experiment was conducted on the treadmill under walking condition with 1.5 km/h speed. Results obtained from the device will be compared with the motion analysis data that will be recorded using high speed camera and Kinovea software specifically for angle measurement. It indicates that both methods can be used in determine ROM and the difference between data collected by both methods is just below than 3.4%. Hence, this study is potentially beneficial for the wireless monitoring system that can be applied in the sport and rehabilitation applications.

Tool wear is a major aspect in metal cutting, especially during steel machining. This studies the capability of 1 mm thick uncoated tungsten carbide insert during the turning of AISI 1017 mild steel. The reduction of insert thickness will lead to a more economical and efficient use of material and energy during fabrication, operation, and disposal of the cutting insert. Axial machining trials have been performed using the finishing cutting conditions. Tool flank wear and workpiece surface roughness were analysed using an optical microscope and contact perthometer device, respectively. The data of flank wear and surface roughness achieved were used to analyse the capability of replacing 4 mm thick cutting inserts with 1 mm thick cutting inserts. The results showed that the flank wear and the surface roughness of conventional inserts performed better as compared to the 1 mm thick insert with a significant difference of 5.74 % and 1.57 %. Thus, the experimental study shows that the 1 mm thick insert performed as good as a conventional cutting insert in terms of tool life and surface roughness quality.

Kenaf fiber has been cultivated as an industrial crop. In this paper, we present the on-going works of an assessment on the mechanical properties of its fiber composites. Tensile, flexural and impact tests were executed on untreated short kenaf fiber reinforced epoxy composites. Its fiber content is varied from 5% up to 20%, and was compared to neat epoxy (NEAT). Using a hand lay-up technique, a mixture of kenaf fiber and epoxy is poured into a mould and left to dry at room temperature for 24 hours. Seven specimens were cut according to ASTM D3039, ASTM D790 and ASTM D256 for the tensile test, flexural test and impact test, respectively. The results showed that the tensile, flexural and impact strengths of the kenaf fiber are lower compared to NEAT. Samples at 5% kenaf fiber content shows the highest tensile strength, flexural strength and impact strength at 27. 1 MPa and 18.2 MPa and 0.56 kJ/m2, respectively. The 5% fiber content was finalized as the fiber content that can be applied in archery.