The factors of students’ involvement on student-centered learning method

Student-centered learning (SCL) is one of the teaching methods commonly used nowadays as it encourages the active participation and engagement of students in the classroom, especially for the engineering theoretical subject. This study is aimed to examine the factors of students’ involvement and participation towards the SCL Teaching Method in terms of the activities, benefits, problems, and limitations of student involvement. The quantitative data are obtained from the responses of students that enroll in an engineering theoretical subject in the Universiti Teknologi MARA (UiTM) Pahang Civil Engineering Diploma Program. These questionnaires were being classified into five major factors that are the formation of group studies for SCL activities, activities conducted for SCL teaching method, benefits that they gain from SCL method, problems that they encounter during SCL, and suggestions for student improvement towards the activity SCL session. The collected data were analyzed quantitatively by using the percentage and mean method in SPSS computer software. The Relative Importance Index (RII) system was used to quantify the relative importance of involvement factors. This study revealed three main factors affecting the participation and engagement of students in the classroom. This study has an important contribution to help academicians to improve and enhance their teaching method to achieve the objective of the SCL method in the future

Kenaf Reinforced PLA Composite Thermoforming: A Numerical Simulation

Recent manufacturing development focuses on the optimum technique of product fabrication that time-consuming and cost-effective including thermoforming process. Fundamental studies on the thermoforming process, especially in the uni-directional direction of kenaf fiber composite are still in preliminary stages. Hence, a numerical simulation is performed in order to minimize the experimental conduct. PAM-FORM software is used for modeling and simulation of the thermoforming process by studying the effect of processing parameters on the results of the simulation. The optimum thermoforming process parameter in terms of temperature, puncher speed, puncher radius and composite thickness are determined by the design of experiments. The output parameters including thinning of the composite, shear angle and stress are analyzed to identify the wrinkling defects which further analyzed using the Design-Expert software. Results demonstrate that at a temperature of 120 °C, puncher speed of 28.78 m/s, puncher radius and composite thickness of 4 mm and 2 mm, respectively able to achieve minimum thinning and minimal shear angle during the thermoforming process

Effect of Multi-walled Carbon Nanotube on Mechanical Properties of Kenaf/Polypropylene Composites / Zakaria Razak...[et al.]

Kenaf fibre has a high potential to be used for composite reinforcement in hybrid composites. It has been varying combinations of physical and mechanical properties, such as low cost, low density, high strength and stiffness. Carbon nanotubes (CNTs) are encouraging additives for polymer composites due to their excellent special mechanical, electrical, and thermal properties. The compounded samples were organized into test specimens by injection moulding machine. The composites contained 1, 2, 3 and 4 wt% multi-walled carbon nanotubes (MWCNT). The purpose of this study is to investigate the mechanical properties of kenaf core fibre with a weight fraction of 30 wt% and varying weight fraction of MWCNT. The injection moulding technique is used to prepare the composite specimens for tensile, flexural and impact tests in accordance to the ASTM D638, ASTM D790 and ASTM D256 respectively. The optimum properties have been observed at MWCNT 3 wt% with the impact strength of, 8.512Kj/m2, tensile strength, 23.447 MPa, Young’s modulus, 1865.950 MPa, flexural strength, 36.728MPa and a flexural modulus, 1826.121 MPa

Effects of Fiber Content and Processing Parameters on Tensile Properties of Unidirectional Long Kenaf Fiber Reinforced Polylactic-Acid Composite / Izdihar Tharazi...[et al.]

Recent developments within the field of natural fiber-reinforced polymer composite have led to a renewed interest in fully biodegradable composite or green composite. Interest in using green composites is due to environmental awareness concerns as well as stringent government regulations. The study is aimed to determine the optimum percentage of fiber content for unidirectional long kenaf fiber (LKF) reinforced polylactic-acid composites. In addition, the influence of processing parameters has also been investigated but only for the optimum fiber content. The percentage of kenaf used are 10 wt% to 50 wt% prepared by film stacking method with a hot-press machine. A series of tensile tests was performed to obtain the tensile strength, including the Young’s modulus of the composite. The 40 wt% fiber composites showed tensile strength, and the Young’s modulus increased linearly to 230% and 650%, respectively. Furthermore, for 50 wt% of fiber content, tensile strength and young modulus increased linearly to 244% and 625% compare to pure polymer, respectively. It was found that better tensile properties were achieved with 50%wt fiber composites produced at a temperature of 200oC, 5MPa compression pressure and 5 minutes holding time. Applications for fabricated compoistes are in non-structural to structural with medium loads, especially in the field of aerospace, automotive, and building construction industries

Mechanical Properties of Compression Molded Epoxy Polymer Composites Reinforced with Kenaf Fibers / Nur Farhani Ismail ...[et al.]

Kenaf composites have been widely used in the engineering and industrial applications such as air cleaner, dashboard, insulation mats, and fibreboard. Due to considerable attentions; kenaf fibres are reinforced in polymers for the fabrication of polymer composites. This work deals with the fabrication and characterizations of untreated and treated temafa kenaf fibres. The microstructure (SEM), flexural properties and tensile properties of the prepared kenaf polymer composites were discussed throughout this study. The kenaf fibres were treated with 6 wt% sodium hydroxide, NaOH solution for 24 hours soaking time. The epoxy thermoset reinforced with randomly oriented temafa kenaf was fabricated using compression molding technique. The composite samples of kenaf were prepared with different kenaf fibre loadings; 20 wt%, 30 wt%, 40 wt%, 50 wt% and 60 wt% . It was found that the properties of kenaf composites mainly depend on the compositions of kenaf fibres. It has also been investigated that the treatment influences the properties of kenaf itself. Overall, the results revealed that the treated kenaf composites have better mechanical properties such as flexural strength as compared to the untreated kenaf composites. However, it is observed that the flexural strength also increased with increasing percentage loading of kenaf fibres. These prepared kenaf composites will perform better mechanical properties than existing polymer may be used in automotive applications

The effects of maleic anhydride grafted PP (MAPP) on the mechanical properties of injection moulded kenaf/CNTs/PP composites

Composite materials have increasingly become crucial in manufacturing engineering products and producing commodity materials in the major industries including; automotive, aerospace, marine, construction, agriculture and health science. However, several improvements regarding the strength, dimensional stability and the cost of production are required. In this study, composite of Kenaf, multi-wall carbon nanotube (MWCNT) and polypropylene (PP) with maleic anhydride-grafted polypropylene (MAPP) are examined. The results highlight that increasing MAPP loading, in turn, increases the value of the mechanical properties. The composites are produced by blending kenaf/MWCNT/PP using a Sigma blade mixer and injection moulding. Injection moulding is a significant operation used to produce plastic products. In the study, Kenaf core fibre was mixed with MWCNT and polypropylene, in addition to MAPP. The MAPP is added by applying different percentage (1, 2, 3 and 4 wt. %) during the blending process. The main objective of the study was to analyse the effects of MAPP concentrations on the mechanical properties of the Kenaf/MWCNT/PP composite. The results of the study established that MAPP 3 wt. % concentration with MWCNT 3 wt. % loading and Kenaf 30 wt. % filler provide optimum results for the composites. There was approximately, a 21% enhance in tensile strength of Kenaf 30 wt. %/MWCNT, 3 wt. %/MAPP, 3 wt. %/PP observed compared to the (without) MAPP composite. The composites with coupling agent stimulate better filler dispersion between Kenaf, MWCNT and PP observed using a scanning electron microscope (SEM) and field-emission scanning electron microscope (FESEM)

Kenaf fiber composites: a review on synthetic and biodegradable polymer matrix

This review paper deals with the previous and current works published on the kenaf fiber composites. Kenaf is grown commercially in South East Asia country and widely used in the construction and infrastructure as well as in the automotive industry. Kenaf fiber is usually reinforced with synthetic based polymer resin such as polypropylene. However, recent studies tend to concern towards the environmental issues which kenaf fiber act as an alternative natural fiber competitor. Moreover, the combination of the natural fiber and the biodegradable polymer able to reduce the negative impact on human health. Hence, researcher-initiated the interest focusing on the biodegradable materials obtained from the renewable sources. A huge attention gave to the kenaf fiber reinforced bio-polymer materials such as polylactic acid. The processing technique and the fiber orientation within the composite materials are discussed extensively in order to obtain the maximum composite performance. Results indicated that the mechanical properties; tensile strength and tensile modulus, are improved as the kenaf fiber was aligned in uni-direction. Therefore, this paper overview on the kenaf retting types in the common form of kenaf fibers and discussing the thermoplastic polymer matrices types used in the fabrication processes. In addition, the challenging of using kenaf fibers composites and its application in the automotive industry also highlighted

Empirical Model and Validation of Bar Formation in Sand Bed Channel

Both present experimental and previous historical data were used to develop the empirical model. Generally, the aim of this study to establish an empirical model of bar formation from the present experimental data and selected historical data. Statistical techniques using Multiple Linear Regression Analysis were employed for empirical model development and the selection of bar formation parameters were done based on the works of previous investigators. Validation of the newly developed empirical model was done by using a different set of historical data from selected laboratory studies. Model development involved selection of parameters through review of established models, dimensional analysis to check on the homogeneity of the model and statistical analysis. Derived empirical model has been validated using a different set of data from previous studies. Analysis confirmed that the empirical model derived using linear regression technique depicts the highest discrepancy ratio accuracy of 90% with Dds${D \over {{d_s}}}$ and BD${B \over D}$ as the most significant parameters that promote bar height formation

Empirical Model and Validation of Bar Formation in Sand Bed Channel

Both present experimental and previous historical data were used to develop the empirical model. Generally, the aim of this study to establish an empirical model of bar formation from the present experimental data and selected historical data. Statistical techniques using Multiple Linear Regression Analysis were employed for empirical model development and the selection of bar formation parameters were done based on the works of previous investigators. Validation of the newly developed empirical model was done by using a different set of historical data from selected laboratory studies. Model development involved selection of parameters through review of established models, dimensional analysis to check on the homogeneity of the model and statistical analysis. Derived empirical model has been validated using a different set of data from previous studies. Analysis confirmed that the empirical model derived using linear regression technique depicts the highest discrepancy ratio accuracy of 90% with ${D \over {{d_s}}}$ and ${B \over D}$ as the most significant parameters that promote bar height formation