Axial vibration mode of coupled liquid-structure-gas system in a rigid cylindrical container

This paper describes the axial vibration analysis of a closed ends rigid cylindrical container containing liquid and gas which separated by a thin circular plate at their interface. The liquid depths inside the container were varied and then the mode of vibration and the natural frequencies were analyzed. The natural frequencies obtained experimentally were compared favorably with those of commercial finite element analysis software, ANSYS. The vibration mode of the liquid-structure interaction of the tank system can be visualized from the software post processing animation/plot. The visualized modes are also consistent with the measurement by the respective experimental transducers. It was found that strong coupling predominantly occur between liquid and structure. In weak coupling conditions, the modes are predominantly gas mod

Mechanical and durability analysis of fly ash based geopolymer with various compositions for rigid pavement applications

Ordinary Portland cement (OPC) is a conventional material used to construct rigid pave�ment that emits large amounts of carbon dioxide (CO2 ) during its manufacturing process, which is bad for the environment. It is also claimed that OPC is susceptible to acid attack, which increases the maintenance cost of rigid pavement. Therefore, a fly ash based geopolymer is proposed as a material for rigid pavement application as it releases lesser amounts of CO2 during the synthesis process and has higher acid resistance compared to OPC. This current study optimizes the formulation to produce fly ash based geopolymer with the highest compressive strength. In addition, the durability of fly ash based geopolymer concrete and OPC concrete in an acidic environment is also determined and compared. The results show that the optimum value of sodium hydroxide concentration, the ratio of sodium silicate to sodium hydroxide, and the ratio of solid-to-liquid for fly ash based geopolymer are 10 M, 2.0, and 2.5, respectively, with a maximum compressive strength of 47 MPa. The results also highlight that the durability of fly ash based geopolymer is higher than that of OPC concrete, indicating that fly ash based geopolymer is a better material for rigid pavement applications, with a percentage of compressive strength loss of 7.38% to 21.94% for OPC concrete. This current study contributes to the field of knowledge by providing a reference for future development of fly ash based geopolymer for rigid pavement applications

Interaction of Geopolymer Filler and Alkali Molarity Concentration towards the Fire Properties of Glass-Reinforced Epoxy Composites Fabricated Using Filament Winding Technique

This paper aims to find out the effect of different weight percentages of geopolymer filler in glass-reinforced epoxy pipe, and which can achieve the best mechanical properties and adhesion between high calcium pozzolanic-based geopolymer matrices. Different weight percentages and molarities of epoxy hardener resin and high calcium pozzolanic-based geopolymer were injected into the glass fiber. By manually winding filaments, composite samples were produced, and they were then allowed to cure at room temperature. To determine how well the geopolymer matrices adhere to the fiber reinforcement, the microstructure of the composites’ surfaces and perpendicular sections were examined. Maximum values of compressive strength and compressive modulus were 94.64 MPa and 2373.58 MPa, respectively, for the sample with a weight percentage of filler loading of 30 wt% for an alkali concentration of 12 M. This is a relatively wide range of geopolymer weight percentage of filler loading from 10 wt% to 40 wt%, at which we can obtain high compressive properties. By referring to microstructural analysis, adhesion, and interaction of the geopolymer matrix to glass fiber, it shows that the filler is well-dispersed and embedded at the fiber glass, and it was difficult to determine the differences within the range of optimal geopolymer filler content. By determining the optimum weight percent of 30 wt% of geopolymer filler and microstructural analysis, the maximum parameter has been achieved via analysis of high calcium pozzolanic-based geopolymer filler. Fire or elevated temperature represents one of the extreme ambient conditions that any structure may be exposed to during its service life. The heat resistance or thermal analysis between glass-reinforced epoxy (GRE) pipe and glass-reinforced epoxy pipe filled with high calcium pozzolanic-based geopolymer filler was studied by investigating burning tests on the samples, which shows that the addition of high calcium pozzolanic-based geopolymer filler results in a significant reduction of the melted epoxy

Characterization and application of dolomite rock in Perlis

Dolomite which is known by the local as ‘batu reput’, is a primary sediment mineral and abundantly found in Perlis. Perlis is one of the major producers of dolomite in Malaysia that contain large deposit of high-purity dolomite [CaMg(CO3)2]. Pure samples of dolomite recently explored in the Koperasi Rimba Mas Padang Besar Quarry were investigated for their physical, chemical and mineralogical composition. The dolomite, was also thermally treated up to 800ºC to decompose the carbonate bonding. SEM with EDS (Energy Dispersive Spectroscopy), XRF and XRD analysis method were applied in this study

Natural Fiber Filament Wound Composites: A Review

In recent development, natural fibers have attracted the interest of engineers, researchers, professionals and scientists all over the world as an alternative reinforcement for fiber reinforced polymer composites. This is due to its superior properties such as high specific strength, low weight, low cost, fairly good mechanical properties, non-abrasive, eco-friendly and bio-degradable characteristics. In this point of view, natural fiber-polymer composites (NFPCs) are becoming increasingly utilized in a wide variety of applications because they represent an ecological and inexpensive alternative to conventional petroleum-derived materials. On the other hand, considerable amounts of organic waste and residue from the industrial and agricultural processes are still underutilized as low-value energy sources. This is a comprehensive review discussing about natural fiber reinforced composite produced by filament winding technique

Biodegradability analysis of KBF reinforced poly(lactic acid) biocomposites

Poly(lactic acid) (PLA) and kenaf bast fiber (KBF) were melt-blended using brabender into films in the PLA/KBF ratios of 100/0, 90/10, 70/30 and 50/50 for natural soil burial test. This formulation was used to study the biodegradability of PLA and PLA/KBF biocomposites. It was found that the decompositions of the biocomposite were faster than pure PLA. The SEM morphology of the tensile fracture surface of the 30% and 50% of PLA/KBF biocomposites presented larger pores and degradation areas than smaller KBF loading (10 wt%). This result shows that the addition of larger fibre loading to the PLA matrix increased the micropore surface area of the PLA/KBF biocomposite hence accelerated the decompositions time of the biocomposites

A Review: Characteristics of Oil Palm Trunk (OPT) and Quality Improvement of Palm Trunk Plywood by Resin Impregnation

Due to the shortage of solid wood as a raw material of plywood and the abundance of oil palm trunk (OPT) waste in Malaysia, OPT has become one of the potential replacements for timber. However, OPT plywood has low performance compared with commercial plywood, due to the poor properties of OPT. There are many recent studies related to quality improvement using thermosetting impregnation, especially with formaldehyde-based resins such as urea formaldehyde (UF) and phenol formaldehyde (PF). Nevertheless, there are very limited studies related to palm trunk plywood using thermoplastic impregnation and formaldehyde-free adhesive. Formaldehyde effects can be avoided by replacing it with a thermoplastic adhesive, such as acrylonitrile butadiene styrene (ABS), to enhance and improve the quality of the plywood manufactured from OPT. In Malaysia, palm trunk plywood is used currently for non-structural materials such as formworks, cabinets, and packaging material. Hence, the enhanced quality of palm trunk plywood with a formaldehyde-free thermoplastic adhesive could produce a higher quality palm trunk plywood

Correlation of manufacturing defects and impact behaviors of kenaf fiber reinforced hybrid fiberglass/Kevlar polyester composite

In this study, the impact properties of kenaf fibre reinforced hybrid fiberglass/Kevlar polymeric composite was investigated. In this study, a new fiber arrangement based on kenaf bast fiber as reinforcement to the hybrid fiberglass/Kevlar fiber and polyester as matrix used to fabricate the hybrid polymeric composite. Five different types of samples with different of kenaf fiber content based on volume fraction (0, 15, 45, 60 and 75%) to hybrid fiberglass/Kevlar polymer composites were manufactured. 0% of kenaf fiber has been used as control sample. The results showed that hybridization has improved the impact properties. These results were further supported through SEM micrograph of the manufacturing defects of the polymer composite. Based on literature work, manufacturing defects that occurs in composite system reduced the mechanical properties of the material. Therefore, in this research the correlation of impact behaviors and manufacturing defects of kenaf fiber reinforced hybrid fiberglass/Kevlar polymeric composite has been successfully done. As conclusion, the highest manufacturing defects determined in the composites during the fabrication significantly lowest the results of impact behavior

Fly Ash Porous Material using Geopolymerization Process for High Temperature Exposure

This paper presents the results of a study on the effect of temperature on geopolymers manufactured using pozzolanic materials (fly ash). In this paper, we report on our investigation of the performance of porous geopolymers made with fly ash after exposure to temperatures from 600 °C up to 1000 °C. The research methodology consisted of pozzolanic materials (fly ash) synthesized with a mixture of sodium hydroxide and sodium silicate solution as an alkaline activator. Foaming agent solution was added to geopolymer paste. The geopolymer paste samples were cured at 60 °C for one day and the geopolymers samples were sintered from 600 °C to 1000 °C to evaluate strength loss due to thermal damage. We also studied their phase formation and microstructure. The heated geopolymers samples were tested by compressive strength after three days. The results showed that the porous geopolymers exhibited strength increases after temperature exposure