Design, Analysis And Fabrication Of Glass Fiber-Reinforced Pa 6,6 Composite Automotive Clutch Pedals

A study of injection number and location is important since it often affects product quality such as weld line and shrinkage as well as process quality such as molding efficiency. This study is also critical because unlike any other processing parameters such as filling speed, pressure and temperature that could be modified instantly, gate location is permanent and any modification equals to increase in cost and time. The main objective of this research is to simulate and analyze the effects of increasing number of gates for a clutch pedal using short glass fiber reinforced PA 6,6. The research compares the effects of a single gated and a double gated mould. A prototype of the composite clutch pedal model is then fabricated and compared with the simulation works. In order to achieve the above-mentioned objectives, two numerical softwares will be used in this study. Moldflow Plastic Insight (MPI) software is used to investigate the effects of mold design on fill time, pressure, temperature, weld line, air traps and fiber orientation and distribution while LUSAS software is used to analyze stress distribution for pedal profiles and rib patterns. The studies show that there are many advantages and disadvantages associated with the design of single and double gated mold. Firstly, a mold designed with a single gate is advantageous in terms of flow balance, fill time and weld line since it provides a more balanced flow, shorter fill time and shorter length of weld line compared to a double gated mold. However, a double gated mold precedes a single gated mold in terms of injection pressure, part shrinkage and trapped air. The study revealed that a double gated mold reduces the required injection pressure as well as pressure variation, hence a lower volumetric shrinkage. Such design also produces less amount of trapped air. Finally, the comparison study of simulation and actual model showed great consistency in terms of fill time, air traps and weld line formations

SPEECH ACT ANALYSIS OF FEMALE STUDENT LEADERS IN A MALAYSIAN SECONDARY SCHOOL

The speech act is a study of pragmatics whereby utterances serve an essential function beyond verbal communication. It is an act of performing some activity through spoken words. In leadership, speech acts play a crucial role in the interaction between leaders and their followers. It not only conveys information but also initiates a desirable action or behaviour among the followers. Thus, leaders must be capable of utilizing different speech acts effectively to influence their followers to act or behave in a specific way and accomplish their leadership goals. This study has been undertaken in response to previous researchers who have found significant differences in speech acts of male and female leaders, with an objective to analyze the speech acts of female student leaders in a Malaysian secondary school according to Theory of Speech Acts by Bach & Harnish (1979). We collected data through in-depth interviews with three research participants who had been selected via purposive sampling. These participants were female students aged 17 years old with at least four years of leadership experience. After an in-depth qualitative analysis of interview data, we have demonstrated that speech acts of the research participants varied among constative, directive, commissive. Constatives, informative, assertive, and predictive acts. Among them, informative, assertive, and predictive speech acts dominated their utterances. In conclusion, the participants' speech acts indicated that, in general, they wished to be persuasive in their leadership roles and responsibilities.  Article visualizations

An Exploratory Study on Linguistic Sexism in Malaysian Secondary School English Literature Textbooks

Linguistic differences between men and women have been a widely popular topic for the last 30 years. This paper is concerned with these differences and how they are represented in todays’ current textbooks. The current study is an attempt to investigate if there is an occurrence of linguistic sexism in the English literature textbooks used in a secondary school in the northern region of Malaysia. The study used two literature textbooks that were currently used by form 4 students in the school. The two books, namely, ‘The Poison Tree’ and ‘A Collection of Short Stories, Poems and Drama’ were examine if linguistic sexism occurred by a critical content analysis (CDA) by Fairclough. This study uses the method of content analysis that was presented by Xu (2009). It is based on the following items: 1. External appearance of female/male characters and 2. Personality of male/female characters .The primary focus of this paper is to see whether linguistic sexism occur in the literature textbooks used in the secondary schools in Malaysia. A qualitative analysis based on the preceding criteria found that the males rule over the females in almost every category linguistically

The Effects of FDM Printing Parameters on the Compression Properties of Polymethylmethacrylate (PMMA) using Finite Element Analysis

3D printing technology has become a favored alternative in fabricating parts due to its flexibility in product customization. Recently, an abundant number of studies have been conducted to improve the overall quality of the 3D printed parts. One of the essential qualities is to provide mechanical properties that fulfill the functionality of the final product. Thus, providing the best option in tailoring the mechanical properties of 3D printed parts is very useful. This paper investigates the effects of printing parameters on the mechanical properties of Polymethylmethacrylate (PMMA) using finite element analysis (FEA). Taguchi's 33 design-of-experiment methods were used to design the experiment for the following printing parameters: shell thickness, type of infill, and infill density. The compressive test was performed using Ansys software and the variables under study were strain and total deformation. The results obtained from the FEA simulation show that the strain and total deformation are mainly influenced by infill density, followed by the type of infill and shell thickness. It is deduced from the study that the optimum printing parameters with higher infill density (70%) and combination with triangular infill pattern able to hold the structure more rigidly, therefore providing more resistance against deformation. This study proposed a platform for determining the mechanical properties of 3D models for FDM printed parts using FEA analysis

Study on tool wear during milling CFRP under dry and chilled air machining

Carbon fibre reinforced plastic (CFRP) is an expensive composite that, as industry demand for this composite has increased, has become a valuable material. CFRP is suitable to be used in automotive, aerospace and aircraft industries, because of its properties, which are being stronger than steel and stiffer than titanium, while retaining its lighter weight. This paper presents the tool wear on solid carbide cutting tool during milling CFRP under dry and chilled air cutting conditions. The experiments were designed by using Central Composite Design (CCD) with range of 160- 200 m/min (cutting speeds), 0.125- 0.25 mm/tooth (feed rate) and 0.5- 1.0 mm (depth of cut). In this study, air pressure of 0.55 MPa and chilled air (with a temperature of -10 Celsius and a flow velocity of 4.10 m/s) were applied to the cutting tool using a vortex tube. The longest tool lives of 7.22 minutes (dry machining) and 7.33 minutes (chilled air machining) were achieved at the lowest feed rate of 0.125 mm/tooth, a cutting speed of 179 m/min, and depth of cut of 0.71 mm. The polished/shined surface of the tool wear area, which was caused by the abrasive nature of carbon and the sliding mechanism of chips during machining, shows the presence of abrasion wear. Less tool wear was observed under chilled air machining conditions than dry machining. Based on the developed mathematical model, feed rate was identified as the primary significant item that influenced tool life. In conclusion, the application of chilled air during CFRP machining helped to improve the tool life of uncoated carbide cutting tools compare to dry machining

Viscosity profiles of phosphate glasses through combined quasi-static and bob-in-cup methods

This study used a combined viscosity approach to determine theoretical fibre drawing points for glasses in the series: xP2O5, 24MgO, 16CaO, (60-x)Na2O (x = 40,45,50,55) and yP2O5, 24MgO, 16CaO, (55-y)Na2O, 5Fe2O3 (y = 40,45,50,55). The points cannot be measured directly since the glasses are only kinetically stable at these points and would crystallise if allowed to equilibrate. Quasi-static and bob-in-cup viscosity data from above and below the range of interest were fitted to the Vogel–Fulcher–Tammann equation and provided good agreement. The theoretical drawing points were taken as the temperature at which the glass has a viscosity of 2 Log Pa·s, based on the known drawing point viscosity of silica glasses. The theoretical drawing points for the glasses ranged from 657 to 839 °C. The viscosity information was also used to assess the fragility of the glasses in comparison with a borosilicate standard by using Doremus and Angell parameters. All of the glasses were of low viscosity and high fragility in comparison to the borosilicate. The fragility improved above 50% content of phosphate in the glass and the addition of iron had little effect on the fragility. Additionally, the limitations of he borosilicate 717a standard glass and the measurement of Tg are discussed

The effects of FDM printing parameters on the compression properties of polymethylmethacrylate (PMMA) using finite element analysis

3D printing technology has become a favored alternative in fabricating parts due to its flexibility in product customization. Recently, an abundant number of studies have been conducted to improve the overall quality of the 3D printed parts. One of the essential qualities is to provide mechanical properties that fulfill the functionality of the final product. Thus, providing the best option in tailoring the mechanical properties of 3D printed parts is very useful. This paper investigates the effects of printing parameters on the compression properties of Polymethylmethacrylate (PMMA) using finite element analysis (FEA). Taguchi's 33 design-of-experiment methods were used to design the experiment for the following printing parameters: shell thickness, type of infill, and infill density. The compressive test was performed using Ansys software and the variables under study were strain and total deformation. The results obtained from the FEA simulation show that the compressive strain and total deformation are mainly influenced by infill density, followed by the type of infill and shell thickness. It is deduced from the study that the optimum printing parameters with higher infill density (70%) and combination with triangular infill pattern are able to hold the structure more rigidly, therefore providing more resistance against deformation. This study proposed a platform for determining the mechanical properties of 3D models for FDM printed parts using FEA analysis

Nitrate in Groundwater and Excretion of Nitrate and Nitrosamines in Urine: A Review

Nitrate is harmful to humans as it can form endogenous nitrosamines which can cause cancer. The major contribution of nitrate contamination in well water is largely from agricultural activities (e.g.; fertilizers and pesticide), wastewater treatment plant discharge, animal yard and manure storage lagoons. Biomarkers such as urine and saliva can be used to determine the occurrence and formation of nitrosamines in the human body. This paper provides an overview of nitrate occurrence in groundwater and the mechanism of nitrosamines formation and its excretion from human body via urine and saliva. The suitability of urine and saliva as biomarkers of endogenous nitrosamines formation were also discussed in this review

Thermal modelling and analysis of batik canting design

Canting or ‘tjanting’ is a traditional hand tool that is used to apply wax in lines and fine dots on a cloth to create beautiful batik designs. In this study, the thermal and structural characteristics of the wax determined via differential scanning calorimetry (DSC) and fourier transform infrared (FTIR) spectroscopy respectively. The actual temperature distribution in the current batik canting was determined using laser thermometer. The model of the canting was then simulated via Solidworks 2013 to obtain the heat distributed along the length of the canting body. The thermal simulation of the canting model revealed that the maximum and minimum temperature were 72.3°C and 32.0°C respectively. The temperature readings obtained were found to be consistent with the actual heat distribution results for the canting with maximum temperature discrepancy between 3-6%. It is envisioned that with more ergonomic and ease of use of the batik tool will enhance the batik making process and industry in Malaysia

Characterization of poly (lactic acid) _ poly (ethylene) glycol blends prepared for melt drawn spinning process

In this study, PLA/PEG blends were prepared using solvent (chloroform) casting methods. PEG was incorporated with increments of 5 wt.% up to 30 wt.% into PLA. Multiple test methods were used to characterize the thermal and structural properties of these blends; Differential Scanning Calorimeter (DSC), Thermogravimetric Analysis (TGA), Fourier Transform Infrared Spectroscopy (FTIR) and optical microscopy (OM). DSC thermograms showed that the incorporation of PEG significantly decreases the glass transition temperature from 55.56°C to 37.35°C and crystallization temperature from 97.14°C to 79°C of the blend. TGA thermograms indicated that the initial and maximum decomposition temperatures for all composition shifted systematically to lower temperature compared to the pure PLA. As the incorporation of PEG into PLA increases, the values of –CH stretching, C=O, C-O wavenumber shifted to lower wavenumber. Lastly, smooth and uniformed fibers were then successfully drawn using an in-house built mini fiber-drawing equipment with an average diameter ranging from 27 to 50 μm