Applied Mechanics and Materials Vol. 735

Abstract: In this study, ethylene vinyl acetate (EVA) was blended with Polylactic acid (PLA) in order to enhance the mechanical properties of PLA. PLA/EVA blend was melt blended in a twin screw extruder and compression molding with various EVA content (0-20% by weight) and the tensile and morphological properties were examined. The morphological behaviours play an important role in influencing the tensile properties of PLA. The smaller discrete EVA particle in PLA matrix had increased the properties of PLA compared with the one with elongated morphology.

Abstract: This study was conducted in order to develop the new polymer nanocomposites. In this case, sepiolite was incorporated into Polyamide 6 (PA6) / Ethylene vinyl acetate (EVA) blend. The main aim of this research is to examine the effect of sepiolite concentration on the properties of PA6/EVA/sepiolite nanocomposite. The variations of sepiolite (2 – 10 phr) were added into PA6/EVA blend at the ratio of 80/20 wt%. The nanocomposites were prepared using twin screw extruder and injection moulding. Mechanical properties of PA6/EVA/sepiolite nanocomposite were analyzed by tensile testing and it was revealed that there is no change in stiffness and decrease in strength with more sepiolite content. Meanwhile, the morphology of materials was characterized by field emission scanning electron microscopy (FESEM). The morphology revealed that, the dispersion of sepiolite nanofiller seems to be good and the EVA domain size and distribution was effected by sepiolite content.

Abstract: Dry machining has been successfully used in several machining applications with different cutting tools and workpiece materials due to its environmental friendliness. Dry hard turning has become an alternative machining process to grinding due to its ability to increase material removal rate, reduce production costs, and enhance of material properties. However, hard turning has several issues such as high temperatures at the tool-chip and tool-workpiece interfaces which are affecting negatively on the surface integrity of the machined parts. Using conventional cutting fluids can improve machining performance by reducing the temperature in the cutting area. However, conventional cutting fluids have some issues such as pollution, hazard on operator, high cost, and corrosion for machine tool and workpiece. All these issues related to applications of conventional cutting fluids have encouraged the researchers to look up for another alternative cooling technique in machining operation. Cooling gas has been explored as one of the alternative cooling techniques. The present paper studies the effect of applying nitrogen gas on surface roughness and tool life under different cutting parameters (cutting speed of 100, 135, and 170 m/min, feed of 0.16, 0.2, and 0.24 mm/rev, with constant depth of cut of 0.2 mm) for hard turning of stainless steel (hardness of 48 HRC) using coated carbide tools. Results showed that better surface finish and longer tool life were achieved by using nitrogen gas coolant condition compared to dry cutting.

Abstract: This work investigates the effect of compatibilizer concentration on the mechanical properties of compatibilized polyethylene terephthalate (PET) /polypropylene (PP) blends. A blend containing 70 % (wt) PET, 30 % (wt) PP and 5 - 15 phr compatibilizers were compounded using counter rotating twin screw extruder and fabricated into standard test samples using injection molding. The compatibilizer used is styrene-ethylene-butylene-styrene grafted maleic anhydride triblock copolymer (SEBS-g-MAH). Morphological studies show that the particle size of the dispersed PP phase is dependent on the compatibilizer content up to 10 phr. Impact strength and elongation at break showed maximum values with the addition of 10 phr SEBS-g-MAH and a corresponding decrease in flexural and young’s moduli; and strengths.. Overall the mechanical properties of PET/PP blends depend on the control of the morphology of the blend and can be achieved by effective compatibilization using 10 phr SEBS-g-MAH.

Abstract: Process equipment failures play significant roles in most accidents that occur and recur in the chemical process industry resulting in fire, explosion, and toxic release. In this study, 50 equipment-related accident investigation reports were used to analyze type and severity of incidents. The comprehensive accident report data were retrieved from U.S. Chemical Safety and Hazard Investigation Board (CSB) and U.S. National Transportation Safety Board (NTSB) accident databases with a mean year of 2005. Among the identified process equipment failures were piping systems (32%), storage tanks (20%), process vessels (16%), separation equipment (10%), reactors (8%), heat transfer equipment (8%), and others (6%). The analysis shows that 32% of the cases led to fire and explosion, followed by toxic release (26%), and explosion (22%) incidents. A total of 126 fatalities, 590 injuries, 260 exposures, four shelter-in-place, and 13 evacuations were reported. In most accident cases, fire, explosion, and/or toxic release incidents occur simultaneously. The synergy between major hazards results in catastrophic accidents with severe consequences in numbers of fatalities, injuries, exposures, shelter-in-place, and evacuations. To minimize the losses, plant and equipment should be designed and prepared for the worst-case scenario, not just adapting to any ‘applicable’ standards or guidance.

Abstract: This paper performs analytical and experimental investigation on the section properties of locally produced cold-formed steel sections. Effective width method given by BS EN1993-1-3 is used to calculate the section properties for two slender cold-formed steel channel sections, namely KS200C20 and KS250C20. Local buckling and distortional buckling are taken into account in the calculation. Effective width method has significantly reduced the full sectional area and thus gives a relative lower value for the sectional resistance of cold-formed steel channel sections. The analytical results is compared to manufacturer’s data and differences of not more than 3.37% is recorded. Experimental study on the flexural behaviour on the two types of cold-formed steel channel sections is carried out. The results show that BS EN1993-1-3 has good agreement with experimental results for flexural resistance that included local and distortional buckling consideration. It is concluded that effective width method by BS EN1993-1-3 is suitable to calculate the section properties of of locally produced cold-formed steel channel sections.

Abstract: Good ventilation is important for passenger for sufficient supply of fresh air during commuting in a bus. Insufficient fresh air causes feeling of uncomfortable to passenger and affects passenger’s health. Airborne transmission disease, headache and respiratory allergies are the usual health symptoms. This paper presents the CFD study of air flow inside a bus passenger compartment. The objective is to estimate the temperature level at the diffuser, seat and floor locations of the bus passenger compartment. Two conditions of airflow velocity at the supply diffuser were examined, namely 2.7 m/s and 3.1 m/s. A CFD Fluent software was employed to develop and meshed a simplified 3D model of a quarter section of a bus passenger compartment. Air velocity and temperature boundary conditions were prescribed on the model based on the actual data obtained from field measurement. Turbulent flow analyses were carried out using standard k-ε model to visualize the air flow distribution inside the compartment. The results show that the velocity distribution is uniform when the diffuser air velocity is 3.1 m/s. When the diffuser air velocity is 3.1 m/s the air temperature of the seat area was decreased by 0.3°C. The air temperature inside the cabin can be maintained uniform at 23°C when diffuser air velocity was fixed at 3.1 m/s.

Abstract: Plastic injection molding machine consume high electricity during manufacturing process which can increase carbon emissions indirectly. The research aim is to generate an energy map for plastic injection molding machine. It involved several experimental investigations by having to record the electrical energy consumption of the machine. The results were than analyzed to develop an energy map for plastic injection molding operation. The results revealed effect of different parameter setting towards electrical energy consumption in injection molding. From this energy map, it can be used by the manufacturer in order to determine the optimized setting parameter in injection molding. This in turn will help to reduce the electrical energy in injection molding process. The reduction of electrical energy will not only reduce the manufacturing cost, but it also can help to reduce the carbon emission emitted during the generation of electrical energy at the power plant. Eventually this research will support sustainable manufacturing processes especially in injection molding industries.

Abstract: In the context of refurbishment projects, providing a safety and health checklist could assist in reducing noncompliance with health and safety regulations and would lead to improvement in communication between different participants in refurbishment projects. The practical checklist for refurbishment project is developed by revising current demolition checklist since there is no specific checklist applicable for refurbishment work at the moment. To achieve this target, demolition techniques, methods and accident reports on the refurbishment project is critically reviewed and investigated. A semi-structured interview based on reviewed literature and existing demolition checklist is organized which addresses a panel of Malaysian refurbishment experts and workers. The final results are provided by analyzing the response of interviewees in listing the common hazards occurring in the site and their recommendations regarding to appropriate precautions to prevent accidents in work site. Finally, refurbishment checklist is developed based on different categories of work phase, activities, precautionary actions and recommendations in which contents directly extracted from data collection and literature review.

Abstract: Reinforced concrete coupled walls are cantilevered shear walls joined by coupling beams and are used in high-rise apartment for many years. Rectangular openings are the most common shape of openings used in shear wall in order to provide doors, windows, entrance to car park areas and elevators or staircases. Behavior of coupling beams affect the strength of coupled walls. This research suggests adding haunches to the corners of rectangular openings and form octagonal openings as a method to increase the strength of coupling beams. The experimental results of shear wall with single band of rectangular and octagonal openings are compared in terms of behavior of coupling beams under cyclic load. The results demonstrate that the coupling beams in shear wall with octagonal openings are stronger than coupling beams in shear wall with rectangular openings.